Section G: Precautions in Attacks

[Commentary]


  1. Aircraft in the air are given a special treatment in this Manual for two reasons. The first reason is their greater vulnerability when they are airborne, since a successful attack has a high likelihood of killing every person onboard, in particular passengers who will normally have no possibility to escape. The second reason is that the speed of modern aircraft is likely to require rapid decision-making relating to identification of their nature as a lawful target that can be attacked in compliance with the law of international armed conflict. These two elements make it necessary to establish, in air and missile warfare, proper procedures designed to implement the law of international armed conflict. In other words, it is not the law that is different, but rather how it plays out in these situations.

  2. With regard to references to ICAO Rules such as the ICAO Manual Concerning Interception of Civil Aircraft,[311] it ought to be borne in mind that these have not been designed for wartime. The ICAO provisions are not a part of the law of international armed conflict proper, but ought to be regarded as valuable guidelines to be adhered to as far as military considerations permit.

  3. The requirement to take all feasible precautions to verify that an aircraft to be attacked is a military objective (see Rule 32 (a) and Rule 35 (a) and, in this subsection, see Rule 40), also applies when a UAV is the intended target of an attack. There is a complementary requirement for Belligerent Parties and Neutrals operating civilian UAVs to take all practicable measures to clearly indicate their civilian status.

  4. Some members of the Group of Experts believed that consideration must also be given to the possibility that aircraft that are shot down in the air may cause collateral damage on the ground (see Rule 14; see also the paragraph 3 of the Commentary on Rule 68 (d)). The majority of the Group of Experts rejected this assertion, based upon the general impracticality of factoring in such eventual collateral damage during an air-to-air engagement. However, the majority of the Group of Experts conceded that there may be exceptional circumstances in some rare instances of air supremacy. In these circumstances, when a military aircraft intends to shoot down an aircraft — other than an armed military aircraft — over densely populated areas, the attack ought to be delayed in order to avoid — or, in any event, to minimize — collateral damage.

  1. Manual Concerning Interception of Civil Aircraft, Consolidation of Current ICAO Provisions and Special Recommendations, 1990, ICAO, Doc 9433—AN/926.

Section G Header

[Commentary]


  1. This Section deals with “active precautions”, which are those precautions that are to be taken by an at-tacking Belligerent Party to protect civilians and civilian objects. The efficacy of achieving the overall objective of protecting the civilian population and civilian objects is also dependent upon the obligation of the Belligerent Party subject to an attack to take “passive precautions” (see Section H). As to the relationship between “active precautions” and “passive precautions”, see Rule 46.

  2. With the exception of Rule 41 (but see paragraphs 7 and 8 of the Commentary on Rule 41), Section G applies in its entirety also in non-international armed conflict.

Categories: Section G: Precautions in Attacks, Section Headers Tags:

Rule 30

Constant care must be taken to spare the civilian population, civilians and civilian objects.

[Commentary]

  1. This Rule is based on Art. 57 (1) to (4) of AP/I.[285] See also Para. 8.1. of NWP.[286]

  2. Rule 30 makes no distinction between military operations in warfare on land, at sea or in the air. As a general principle, the same norms apply equally in all domains of warfare. It is true that Art. 49 (3) of AP/I[287] and Art. 57 (4) of AP/I[288] imply some form of distinction between the conduct of military operations at sea or in the air compared to land. However, the Group of Experts reached the conclusion that, as a general principle, the same legal regime applies equally in all domains of warfare (land, sea or air ).

  3. “Constant care” means that there are no exceptions from the duty to seek to spare the civilian population, civilians and civilian objects.

  4. The Group of Experts noted that there are some objects which, although not civilian objects in the strict sense of the term, are nevertheless subject to the application of Rule 30. A prominent example is that of POW-camps, which are evidently military installations. The Group of Experts could not see any good reason why in practice there ought to be a distinction between them and civilian objects as regards the application of constant care.

  1. Art. 57 of AP/I (“Precautions in attack”): “(1) In the conduct of military operations, constant care shall be taken to spare the civilian population, civilians and civilian objects. (2) With respect to attacks, the following precautions shall be taken: (a) those who plan or decide upon an attack shall: (i) do everything feasible to verify that the objectives to be attacked are neither civilians nor civilian objects and are not subject to special protection but are military objectives within the meaning of paragraph of Article 52 and that it is not prohibited by the provisions of this Protocol to attack them; (ii) take all feasible precautions in the choice of means and methods of attack with a view to avoiding, and in any event to minimizing, incidental loss or civilian life, injury to civilians and damage to civilian objects; (iii) refrain from deciding to launch any attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated; (b) an attack shall be cancelled or suspended if it becomes apparent that the objective is not a military one or is subject to special protection or that the attack may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated; (c) effective advance warning shall be given of attacks which may affect the civilian population, unless circumstances do not permit. (3) When a choice is possible between several military objectives for obtaining a similar military advantage, the objective to be selected shall be that the attack on which may be expected to cause the least danger to civilian lives and to civilian objects. (4) In the conduct of military operations at sea or in the air, each Party to the conflict shall, in conformity with its rights and duties under the rules of international law applicable in armed conflict, take all reasonable precautions to avoid losses of civilian lives and damage to civilian objects.”

  2. Para. 8.1 of NWP (“Principles of lawful targeting”): “The law of targeting … requires that all reasonable pre-cautions must be taken to ensure that only military objectives are targeted so that noncombatants, civilians, and civilian objects are spared as much as possible from the ravages of war.”

  3. Art. 49 (3) of AP/I: “The provisions of this section apply to any land, air or sea warfare which may affect the civilian population, individual civilians or civilian objects on land. They further apply to all attacks from the sea or from the air against objectives on land but do not otherwise affect the rules of international law applicable in armed conflict at sea or in the air.”

  4. Art. 57 (4) of AP/I, see fn. 285.

Categories: G: General Rules Tags:

Rule 31

All feasible precautions must be taken to spare all persons and objects entitled to specific protection under Sections K, L, M and N of this Manual.

[Commentary]

  1. The reference to feasible precautions in this Rule is based on Art. 57 (2) (a) (i) of AP/I.[289]

  2. The term “feasible” is defined in Rule 1 (q). The expression “feasible precautions”, referred to in Rule 31, embraces precautions relating to (i) the general protection to which all civilian objects are entitled; and (ii) the specific protection as detailed in Sections K, L, M and N.

  3. All civilian objects enjoy general protection. Specific protection means that the law of international armed conflict provides for specific safeguards for the protection of particular objects. These safeguards come in addition to the general protection these objects enjoy as civilian objects.

  1. Art. 57 (2) (a) (i) of AP/I, see fn. 285.

Categories: G: General Rules Tags:

Rule 32

Constant care includes in particular the following precautions:

[Commentary]

(a) Doing everything feasible to verify, based on information reasonably available, that a target is a lawful target and does not benefit from specific protection;

[Commentary]

(b) Doing everything feasible to choose means and methods of warfare with a view to avoiding – or, in any event, minimizing – collateral damage; and

[Commentary]

(c) Doing everything feasible to determine whether the collateral damage to be expected from the attack will be excessive in relation to the concrete and direct military advantage anticipated.

[Commentary]

  1. This Rule is based on Art. 57 (2) (a) of AP/I.[290] See also Para. 8.1[291] and Para. 8.3.1[292] of NWP.

  2. The purpose of feasible precautions is to avoid attacks being directed at civilians, civilian objects or objects entitled to specific protection and, when attacking military objectives, to avoid — or, in any event, minimize — collateral damage (see Rule 14).

  1. Art. 57 (2) (a) of AP/I, see fn. 285.

  2. Para. 8.1 of NWP, see fn. 286.

  3. Third, fourth and fifth sentences of Para. 8.3.1 of NWP (“Incidental Injury and Collateral Damage”): “Naval commanders must take all reasonable precautions, taking into account military and humanitarian considerations, to keep civilian casualties and damage to the minimum consistent with mission accomplishment. In each instance, the commander must determine whether the anticipated incidental injuries and collateral damage would be excessive, on the basis of an honest and reasonable estimate of the facts available to him. Similarly, the commander must decide, in light of all the facts known or reasonably available to him, including the need to conserve resources and complete the mission successfully, whether to adopt an alternative method of attack, if reasonably available, to reduce civilian casualties and damage.”

  1. To facilitate verification that a target is a lawful target and does not benefit from specific protection, command echelons must utilize all technical assets (such as intelligence, reconnaissance and surveillance systems) at their disposal, to the extent that these assets are reasonably available, and utilizing them is militarily sound in the context of the overall air campaign.

  2. Verification must be based on sources of information that are sufficiently up-to-date and reliable, according to sound military practice. “Information” includes military intelligence. The quality and timeliness of the intelligence has to be considered. It must be taken into account that the enemy may attempt to provide disinformation (see Rule 116 (b)) or otherwise frustrate target intelligence activity. Other information, such as “on the spot” visual observations that may corroborate or contradict military intelligence, must also be taken into account (see, in this respect, Rule 35). All information gathered has to be evaluated on the basis of the circumstances prevailing at the time.

  3. All feasible efforts must be undertaken to obtain reliable information, which may affect the application of the “constant care” rule. Any person planning, ordering or executing an attack can only act on information that is available in the sense that it can be obtained by reasonable efforts. Several States (e.g., Austria) have made statements upon ratification of AP/I, pertaining to Art. 57 (2) thereof, that the latter provision will be applied on the understanding that, “with respect to any decision taken by a military commander, the information actually available at the time of the decision is determinative”.

  4. The feasibility of applying the precautions requirement for the purposes on the “constant care” rule depends on the level of command and on the availability of information. The information available to the aviator on the scene may be different from the information on which command echelons at a distance from the scene are basing their decisions. The aviator may perform real-time observations that negate the information on which the decision to attack was based. The commander may, on the other hand, know more about the overall objectives of the attack than the aviator does and have access to information from sources that are not immediately available to the aviator, such as satellites or human intelligence sources. Therefore, the question for the aviator is whether the commander’s determination is evidently faulty in view of what is visible on site. In this respect, see Rule 35.

  5. In order to exercise constant care, a Belligerent Party ought to retain a command and control system capable of collecting, processing relevant information, making the necessary evaluation and directing its combat units accordingly.

  6. For the specifics of attacks directed at aircraft in the air, see Rule 40.

  1. This Rule is derived from the general principle of proportionality, which is dealt with in Rule 14.
  2. Means and methods of warfare include weapons, weapons systems and munitions, as well as tactics (such as timing, angle and altitude of attack). The term “means of warfare” is defined in Rule 1 (t). The term “methods of warfare” is defined in Rule 1 (v). The term “weapon” is defined in Rule 1 (ff). “Collateral damage” is defined in Rule 1 (l).
  3. Rule 32 (b) imposes a requirement to consider alternative weapons and tactics to avoid — or, in any event, to minimize — collateral damage. For instance, an attacker ought to choose a weapon with greater precision or lesser explosive force if doing so would minimize the likelihood of collateral damage, assuming the selection is militarily feasible (for the definition of feasible, see Rule 1 (q)). Rule 32 (b) also raises the question as to whether the attacker must choose the most precise weapons available. For a discussion thereof, see Rule 8.
  4. Similarly, angle of attack is one of the factors that determine where a bomb may land if it falls short of, or beyond, the target. Thus, to spare a building located, e.g., to the west of a target, it may be advisable to attack from the north or the south.
  5. Rule 32 (b) further entails that it would be prohibited to conduct air or missile attacks against military objectives without using appropriate and available target identification or weapon guidance technologies to aim the weapon at those objectives when such assets are available and their use is militarily feasible.[293] If such assets are not available, and the attacker for this reason is not able to comply with the prohibition against indiscriminate attacks (Rule 13), the attack has to be cancelled (see Rule 35). This general rule is particularly relevant if the military objectives are located in a densely populated area.
  6. “Dual-use” objects — such as airports being used by both civilian and military aircraft — are of particular relevance when it comes to applying Rule 32 (b). Assuming that it is sufficient to put an airfield out of use temporarily, the attacker ought to consider the option of cratering the runway instead of attacking the permanent facilities. This will ensure collateral damage to civilians or civilian objects is avoided, or any event minimized.

  1. Para. 5.32.5 of the UN Manual (“Factors to be considered”): “In considering the means or methods of attack to be used, a commander should have regard to the following factors: (a) the importance of the target and the urgency of the situation; (b) intelligence about the proposed target — what it is being, or will be, used for and when; (c) the characteristics of the target itself, for example, whether it houses dangerous forces; (d) what weapons are available, their range, accuracy and radius of effect; (e) conditions affecting the accuracy of targeting, such as terrain, weather, and time of day; (f) factors affecting incidental loss or damage, such as the proximity of civilians or civilian objects in the vicinity of the target or other protected objects or zones and whether they are inhabited, or the possible release of hazardous substances as a result of the attack; (g) the risks to his own troops of the various options open to him.”

  1. The commander is expected to make an honest assessment of the collateral damage to be expected from the attack, taking into account factors such as known effects of the weapons that are to be used; the vulnerability of any civilian buildings in the target area; the number of civilians that are likely to be present in the target area at the particular time; and whether they have any possibility to take cover before the attack takes place.
  2. As indicated in the Commentary on Rule 32 (a), the reality on the ground may appear to an aviator to be different from the one received during the premission briefing. In this respect, see Rule 35 (c).
  3. As for “dual-use” objects, and the need to avoid — or, in any event, minimize — expected collateral damage that is excessive compared to the military advantage anticipated, see paragraph 5 of the Commentary on Rule 32 (b).
  4. The notion of excessive collateral damage is explained in the Commentary on Rule 1 (l) and in the Commentary on Rule 14.

Categories: G: General Rules Tags:

Rule 33

When a choice is possible between several military objectives for obtaining a similar military advantage, the objective to be selected must be the one where the attack may be expected to cause the least danger to civilian lives and to civilian objects, or to other protected persons and objects.

[Commentary]

  1. This Rule is based on Art. 57 (3) of AP/I.[294] The term “military advantage” is defined in Rule 1 (w).

  2. Rule 33 deals with choice between targets. A useful scenario would involve two rivers across which a road used by the enemy passes. In this scenario, destroying a bridge spanning either of the rivers will effectively cut the road and deny its use to the enemy. If the two bridges are considered to provide equal military advantage, the bridge selected for attack must be that likely to result in the least danger to civilian lives and to civilian objects, or to other protected persons and objects. Similarly, it may be militarily feasible to attack facilities providing power to a military objective rather than the military objective itself. Assuming that the military advantage is equal, this option must be chosen if less danger to civilian lives and to civilian objects, or other protected persons and objects, is expected.

  3. “Similar military advantage” must be understood in terms of the military advantage anticipated from the attack considered as a whole and not only from isolated or particular parts of the attack. The emphasis is on the fact that two or more military objectives can alternatively be attacked. The military advantage anticipated from each alternative attack must be considered as a whole, and not in isolation. Thus, when several parallel bridges have to be destroyed in order to break an axis of communications — and the military advantage that can be achieved depends on the destruction of all the bridges — destruction of only one of them will serve little or no practical purpose. See also paragraph 6 of the Commentary on Rule 1 (w), paragraph 7 of the Commentary on Rule 1 (y) and paragraph 11 of the Commentary on Rule 14.

  4. For the sake of analysis, it may be a hypothesis that there is a terrain which includes a river barrier and behind it a high mountain, the river being crossed by three bridges and the mountain traversed through a tunnel. If, insofar as the river is concerned, the only practical option is to destroy all three bridges — inasmuch as destroying only one or two of them will leave the river passable — it ought to be considered whether it is feasible, instead, to block the tunnel. The latter option will deny the enemy the use of the axis of communication without any practical need to destroy any of the bridges. It is posited that the bridges and the tunnels are “dual-use” targets, because civilians (especially refugees) use them at the same time as enemy armed forces. If so, the expected collateral damage to be assessed is that resulting from an attack on all three bridges versus the collateral damage expected from the attack on that single tunnel.

  5. Another example would be an intended attack against a power generating facility located in the vicinity of civilians or civilian objects, which provides essential power to the civilian population. If the sole objective is to temporarily disrupt power to enemy forces, it might be possible in the circumstances to conduct the attack against the transformers or substations serving the power generating facility. If the attack against the transformers or substations “may be expected to cause the least danger to civilian lives and to civilian objects”, then this is the attack that needs to be preferred over an attack against the power generating facility itself.

  6. It is to be understood that, for Rule 33 to apply, a choice has to be possible between several military objectives for obtaining a similar military advantage. There is no requirement to select among several objectives if doing so would be militarily unreasonable. As an example, if a choice has to be made between two alternative military objectives — one of which is more densely defended than the other — the attacker is not required to select the latter when heavy casualties are anticipated to the attacking force.[295]

  1. Art. 57 (3) of AP/I, see fn. 285.

  2. NIAC Manual to SRM/ACS, page 28, Para. 9: “… there is no requirement to select an objective if doing so would be militarily ‘unreasonable’. As an example, one of the possible objectives may be so much more heavily defended than the others, that it would be unreasonable to select it as the target. Risk to the attacker is a relevant factor. Munitions availability is another. Aside from the fact that certain systems may be unavailable, the attacker will need to take into account future requirements and replenishment. For instance, when the number of precision-guided munitions is limited, it would be imprudent for the attacker to expend them early in the conflict without considering possible future needs and capabilities.”

Categories: G: General Rules Tags:

Rule 34

Constant care must be taken by all those involved in planning, ordering and executing air or missile combat operations to spare the civilian population, civilians and civilian objects.

[Commentary]

  1. This Rule is an application of Rules 31–33 of this Manual to the specifics of air or missile combat operations (see Rule 1 (c)). See also Para. 5.32.9. of the UK Manual.[296]

  2. “Planning” includes all elements necessary to the issuance of an operations order, such as preparation of targeting decisions, recommendations on means of warfare and means of delivery, flight path, suppression of enemy defences and ancillary activities such as warnings.

  3. “Ordering” means deciding on the implementation of a particular plan and the issuance of instructions such as an air tasking order to those involved in the execution.

  4. “Executing” is not limited to the actual use of means of warfare, but extends to those who provide running directions or information from control units in the air or on the surface, provide targeting data by coordinates, laser designation or other means, or otherwise participate directly in ensuring that the operations order is carried out. This could for instance be an AWACS or a joint terminal attack controller (JTAC) on the ground.

  1. Para. 5.32.9 of the UK Manual (“Level of responsibility”): “The level at which the legal responsibility to take precautions in attack rests is not specified in Additional Protocol I. Those who plan or decide upon attacks are the planners and commanders and they have a duty to verify targets, take precautions to reduce incidental damage, and refrain from attacks that offend the proportionality principle. Whether a person will have this responsibility will depend on whether he has any discretion in the way the attack is carried out and so the responsibility will range from commanders-in-chief and their planning staff to single soldiers opening fire on their own initiative. Those who do not have this discretion but merely carry out orders for an attack also have a responsibility: to cancel or suspend the attack if it turns out that the object to be attacked is going to be such that the proportionality rule would be breached.”

Categories: G: Specifics of Air or Missile Operations Tags:

Rule 35

In carrying out air or missile combat operations, an attack must be cancelled or suspended if it becomes apparent:

[Commentary]

(a) That the target is not a lawful target; or

[Commentary]

(b) That the target is and remains entitled to specific protection in accordance with Sections K, L, M and N of this Manual; or

[Commentary]

(c) That the expected collateral damage is excessive in relation to the concrete and direct military advantage anticipated.

[Commentary]

  1. The three conditions of this Rule are derived from Art. 57 (2) of AP/I.[297] See also para. 46 (d) of the SRM/ACS.[298]

  2. The three conditions set out in Rule 35 apply the more general norms of Rule 32 to the specific context of air or missile warfare. Rule 35 (a) applies Rule 32 (a); Rule 35 (b) applies Rule 31; and Rule 35 (c) applies Rule 14.

  3. Rule 35 applies not only to command echelons planning or ordering an attack. It also applies to aircrews (or operators of UCAVs) executing it when it becomes apparent to them that conditions of Rule 35 (a), Rule 35 (b), or Rule 35 (c), or a combination thereof, applies.

  4. Even though Rule 35 is phrased in mandatory language (“must”), it has to be reasonably interpreted. That is to say, the presupposition is that aircrews are in a position to actually cancel or suspend an attack.

  5. It must be borne in mind that aircrews may have more or less information than others involved in the planning or execution of attacks, depending on the circumstances of the case. See paragraph 4 of the Commentary on Rule 32 (a). If onsite information makes it clear to the aircrews that any one of the three conditions of this Rule applies, they have to cancel or suspend the attack on their own initiative.

  6. The requirement of cancellation of missile attacks is relevant not only to externally controlled and guided missiles, but also to the launching of successive waves of ballistic missiles.

  7. For the specifics of attacks directed against aircraft in the air, see Rule 40.

  8. Rule 35 applies also in non-international armed conflict.

  1. Art. 57 (2) of AP/I, see fn. 285.

  2. Support can also be found in Para. 46 (d) of the SRM/ACS: “With respect to attacks, the following precautions shall be taken: … (d) an attack shall not be launched if it may be expected to cause collateral casualties or damage which would be excessive in relation to the concrete and direct military advantage anticipated from the attack as a whole; an attack shall be cancelled or suspended as soon as it becomes apparent that the collateral casualties or damage would be excessive.”


For the list of lawful targets, see Rule 10 (b).

The Sections referred to deal with medical units and medical transports; medical aircraft; the natural environment and other protected persons and objects.

This is the principle of proportionality (see Rule 14).
Categories: G: Specifics of Air or Missile Operations Tags:

Rule 36

In order to avoid the release of dangerous forces and consequent severe losses among the civilian population, particular care must be taken if works and installations containing dangerous forces, namely dams, dykes and nuclear electrical generating stations (as well as installations located in their vicinity) are attacked.

[Commentary]

  1. This Rule is confined to dams, dykes and nuclear electrical generating stations (as well as to installations located in their vicinity). It does not apply to any other work or installation containing dangerous forces. Thus, e.g., facilities such as petrochemical industry plants are not covered by Rule 36. For an attack on the latter, Rules 30–33 apply. Under general customary international law, feasible precautions have to be taken when the latter are being attacked, in order to avoid — or, in any event, minimize — collateral damage which may be caused, e.g., by the release of harmful agents.

  2. Art. 56 of AP/I[299] provides that the works and installations referred to in Rule 36 cannot be attacked, even when they are military objectives, if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population. There is general agreement that Art. 56 of AP/I does not constitute customary law,[300] and it follows that Contracting Parties to AP/I are therefore bound by a higher level of protection than that required under customary law.

  3. However, non-Contracting Parties to AP/I acknowledge[301] that the civilian population enjoys protection against excessive collateral damage expected from attacks on dams, dykes and nuclear electrical generating stations, as laid down in Rule 14. In any event, as Rule 36 clarifies, particular care must be taken in order to avoid the release of dangerous forces resulting in severe losses among the civilian population.

  4. Under Art 56 (2) and (3) of AP/I, there is a possibility of loss of protection for such installations. However, this is subject to specific restrictions.

  1. Art. 56 of AP/I (“Protection of works and installations containing dangerous forces): “(1) Works or installations containing dangerous forces, namely dams, dykes and nuclear electrical generating stations, shall not be made the object of attack, even where these objects are military objectives, if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population. Other military objectives located at or in the vicinity of these works or installations shall not be made the object of attack if such attack may cause the release of dangerous forces from the works or installations and consequent severe losses among the civilian population. (2) The special protection against attack provided by paragraph 1 shall cease: (a) for a dam or a dyke only if it is used for other than its normal function and in regular, significant and direct support of military operations and if such attack is the only feasible way to terminate such support; (b) for a nuclear electrical generating station only if it provides electric power in regular, significant and direct support of military operations and if such attack is the only feasible way to terminate such support; (c) for other military objectives located at or in the vicinity of these works or installations only if they are used in regular, significant and direct support of military operations and if such attack is the only feasible way to terminate such support. (3) In all cases, the civilian population and individual civilians shall remain entitled to all the protection accorded them by international law, including the protection of the precautionary measures provided for in Article 57. If the protection Ceases and any of the works, installations or military objectives mentioned in paragraph 1 is attacked, all practical precautions shall be taken to avoid the release of the dangerous forces. (4) It is prohibited to make any of the works, installations or military objectives mentioned in paragraph 1 the object of reprisals. (5) The Parties to the conflict shall endeavour to avoid locating any military objectives in the vicinity of the works or installations mentioned in paragraph 1. Nevertheless, installations erected for the sole purpose of defending the protected works or installations from attack are permissible and shall not themselves be made the object of attack, provided that they are not used in hostilities except for defensive actions necessary to respond to attacks against the protected works or installations and that their armament is limited to weapons capable only of repelling hostile action against the protected works or installations. (6) The High Contracting Parties and the Parties to the conflict are urged to conclude further agreements among themselves to provide additional protection for objects containing dangerous forces. (7) In order to facilitate the identification of the objects protected by this article, the Parties to the conflict may mark them with a special sign consisting of a group of three bright orange circles placed on the same axis, as specified in Article 16 of Annex I to this Protocol [Article 17 of Amended Annex]. The absence of such marking in no way relieves any Party to the conflict of its obligations under this Article.”

  2. See ICRC Customary IHL Study, Rule 42 and the discussion at pages 139–141.

  3. Para. 8.9.1.7 of NWP: “Dams, dikes, levees, and other installations, which if breached or destroyed would release flood waters or other forces dangerous to the civilian population, should not be bombarded if the anticipated harm to civilians would be excessive in relation to the anticipated military advantage to be gained by bombardment. Conversely, installations containing such dangerous forces that are used by belligerents to shield or support military activities are not so protected. (See paragraph 8.5.1.2.).”

Categories: G: Specifics of Air or Missile Operations Tags:

Rule 37

When the attack of a lawful target by air or missile combat operations may result in death or injury to civilians, effective advance warnings must be issued to the civilian population, unless circumstances do not permit. This may be done, for instance, through dropping leaflets or broadcasting the warnings. Such warnings ought to be as specific as circumstances permit.

[Commentary]

  1. This Rule is based on Art. 57 (2) (c) of AP/I,[302] as well as on Art. 26 of the 1907 Hague Regulations.[303] See also Art. 6 (4) of the 1996 Amended Protocol II to the CCW.[304]

  2. Considering that it is based on the 1907 Hague Regulations, the warning obligation can be considered customary law.

  3. Art. 57 (2) (c) of AP/I uses the term “may affect the civilian population”. So does Art. 6 (4) of the 1996 Amended Protocol II to the CCW. However, Rule 37 of this Manual applies only to air or missile combat operations that “may result in death or injury to civilians”.

  4. Rule 37 does not come into play when a particular air or missile combat operations may result only in damage to, or destruction of, civilian objects. Neither does it come into play in case the attack results in mere inconveniences to civilians caused by, e.g., electrical blackouts or reduced mobility due to broken lines of communications.

  5. There was disagreement among members of the Group of Experts as to whether the duty to issue warnings is limited to civilians located in close proximity to the target.[305]

  6. The term “unless circumstances do not permit” is meant to reflect principally the fact that issuance of an advance warning to the civilian population would deprive the attacker of the element of surprise and may allow the defender to enhance target area defences. If a military combat operation is predicated on the element of surprise, no warning is obligatory in relation to that attack.

  7. The term “as specific as circumstances permit” indicates that the degree of specificity of the warning may depend on further factors such as (i) the length of time prior to the attack in relation to which the warning is issued; and (ii) the most effective mode in which the effective warning can be issued to civilians.

  8. The Group of Experts could not determine (i) the level of the commander who is supposed to issue the warning; or (ii) the geographic extent to which the warning must apply. There was unanimity among the members of the Group of Experts, however, that irrespective of the level of the commander and the geographic extent of the warning, it must be “effective” by reaching the civilians likely to suffer death or injury from the attack.

  9. In this context, the mode of warning issued to the civilian population may depend on available equipment and other factors affecting its feasibility, such as enemy defences that make the dropping of leaflets from the air impracticable. It is also necessary to consider factors bearing on the effectiveness of the warning. As for timing, an imprecise warning issued well in advance of the attack may be more effective than a precise warning immediately preceding it. Similarly, a warning issued well in advance of the attack — reaching only a certain part of the civilian population — may be more effective than one reaching the entire civilian population, which is issued just prior to the attack.

  10. Warnings ought not be vague but be as specific as circumstances permit to allow the civilian population to take relevant protective measures, like seeking shelter or staying away from particular locations.

  11. In some situations the only feasible method of warning may be to fire warning shots using tracer ammunition, thus inducing people to take cover before the attack.

  12. Warnings have to be made in a language that is understood by the local population.

  13. “[B]roadcasting” means not only radio broadcasts but also telecasting and other means such as internet announcements.

  14. Warnings must not be abused as a means of spreading terror among the civilian population. See Rule 18 that prohibits acts or threats of violence in the course of air or missile operations pursued for the sole or primary purpose of spreading terror among the civilian population.

  15. Warnings need not be formal in nature. They may be issued either verbally or in writing, or through any other means that can reasonably be expected to be effective under the circumstances.

  16. An effective warning does not make an unlawful attack lawful, nor does it divest the attacker from its other obligations to take feasible precautionary measures.

  1. Art. 57 (2) (c) of AP/I, see fn. 285.

  2. Art. 26 of the 1907 Hague Regulations: “The officer in command of an attacking force must, before commencing a bombardment, except in cases of assault, do all in his power to warn the authorities.”

  3. Art. 6 (4) of the 1996 Amended Protocol II to the CCW, see fn. 169.

  4. Para. 8.9.2 of NWP (“Warning before Bombardment”): “Where the military situation permits, commanders should make every reasonable effort to warn the civilian population located in close proximity to a military objective targeted for bombardment. Warnings may be general rather than specific lest the bombarding force or the success of its mission be placed in jeopardy.”

Categories: G: Specifics of Air or Missile Operations Tags:

Rule 38

Effective advance warnings must also be given before attacking persons and objects entitled to specific protection under Section K, L and N (I and II), as provided for in these Sections, as well as under Section J.

[Commentary]

  1. This Rule is based on Art. 21 of GC/I (medical units).[306] See also the first paragraph of Art. 34 of GC/II (hospital ships),[307] Art. 19 of GC/IV (civilian hospitals),[308] Art. 13 of AP/I (civilian medical units), and Art. 65 (1) of AP/I (civil defence),[309] as well as Art. 11 (1) of the 1954 Hague Convention (cultural property).[310]

  2. The relevant Rules in the Sections referred to are: (i) Rule 70 in Section J; (ii) Rule 74 in Section K; (b); (iii) Rule 83 in Section L; (iv) Rule 92 in Section N (I); (v) Rule 96 in Section N (II).

  3. The reference in Rule 38 to Sections J, K, L and N (I) and N (II) subjects the general norms to the specific nuances of the warning requirement, as reflected in each specific Section. For example, note has to be taken of the less than settled nature of the obligation to issue advance warning once cultural property has become a military objective (see Rule 96).

  4. Advance warnings before attacks in cases of “misuse” of objects entitled to specific protection differ from warnings according to Rule 37 in that the purpose of warnings under the Rule 38 would be to put an end to the misuse, so that the attack would not be necessary and could be cancelled. By contrast, warnings according to Rule 37 have no such purpose and only convey the information that an attack will take place in the near future, with a view to avoiding — or, in any event, minimizing — collateral damage to the civilian population or to civilian objects.

  5. Warnings that are intended to put an end to misuse should include a time limit to redress the situation, to the extent that circumstances permit.

  6. Warnings need not be formal in nature. See paragraph 15 of the Commentary on Rule 37.

  1. Art. 21 of GC/I, see fn. 414.

  2. First paragraph of Art. 34 of GC/II: “The protection to which hospital ships and sick-bays are entitled shall not cease unless they are used to commit, outside their humanitarian duties, acts harmful to the enemy. Protection may, however, cease only after due warning has been given, naming in all appropriate cases a reasonable time limit, and after such warning has remained unheeded.”

  3. Art. 19 of GC/IV: “The protection to which civilian hospitals are entitled shall not cease unless they are used to commit, outside their humanitarian duties, acts harmful to the enemy. Protection may, however, cease only after due warning has been given, naming, in all appropriate cases, a reasonable time limit and after such warning has remained unheeded. The fact that sick or wounded members of the armed forces are nursed in these hospitals, or the presence of small arms and ammunition taken from such combatants and not yet handed to the proper service, shall not be considered to be acts harmful to the enemy.”

  4. Art. 65 (1) of AP/I, see fn. 530.

  5. Art. 11 (1) of the 1954 Hague Convention: “If one of the High Contracting Parties commits, in respect of any item of cultural property under special protection, a violation of the obligations under Art. 9, the opposing Party shall, so long as this violation persists, be released from the obligation to ensure the immunity of the property concerned. Nevertheless, whenever possible, the latter Party shall first request the cessation of such violation within a reasonable time.”

Categories: G: Specifics of Air or Missile Operations Tags:

Rule 39

The obligation to take feasible precautions in attack applies equally to UAV/UCAV operations.

[Commentary]

  1. The law of international armed conflict has no provisions that are specific to UAV/UCAV. Therefore, the general requirements to take feasible precautions apply. The fact that a UAV/UCAV is unmanned does not relieve an attacker of taking such precautions. For the definition of UAV, see Rule 1 (dd). For the definition of UCAV, see Rule 1 (ee).

  2. UAVs can be a useful asset in complying with the obligation to take feasible precautions in attack. UAVs with on-board sensors will contribute to verification that an intended target is a lawful target (see Rule 32 (a) and Rule 35 (a)). Hence, if available and when their use is feasible, UAVs ought to be employed in order to enhance reliability of collateral damage estimates (especially when this can be done in real-time).

  3. With regard to remotely piloted UCAVs, UCAV operators must employ on-board and/or other reasonably available sensors and sources of intelligence, to the extent feasible, to verify the target and assess expected collateral damage (see Rule 32 (c) and Rule 35 (c)). The fact that the UCAV is unmanned does not necessarily detract from the reliability of information on which the decision to attack is based. Indeed, such assessments by remote operators may be more reliable than those of aircrews on the scene facing enemy defences and other distractions.

  4. In case of autonomous systems, the UCAV must only be programmed to engage potential targets based on reliable information that they are lawful targets. The performance of the sensors and the program identifying lawful targets must be comparable to that of manned aircraft or to that of remotely piloted (i.e. non-autonomous) UCAVs.

  5. The standards set forth in Rule 12 regarding doubt apply equally to UCAV attacks, whether autonomous or manned.

  6. When feasible, the options of using UCAVs in lieu of manned aircraft or other weapon systems, or vice versa, ought to be considered in determining how best to attack a target while avoiding — or, in any event, minimizing — collateral damage. For instance, use of a UCAV in circumstances in which visual identification of the target is necessary — either to reliably verify the target or to avoid excessive collateral damage — may be called for if defensive actions by the defending forces would likely impede visual identification by aircrews. Alternatively, a manned aircraft rather than a UCAV may be called for when its sensors are superior to those of a UCAV or where the visual identification by aircrews would be more reliable than images transmitted from the UCAV’s sensors to its operator.

Categories: G: Specifics of Air or Missile Operations Tags:

Rule 40

Before an aircraft is attacked in the air, all feasible precautions must be taken to verify that it constitutes a military objective. Verification ought to use the best means available under the prevailing circumstances, having regard to the immediacy of any potential threat. Factors relevant to verification may include:

[Commentary]

(a) Visual identification.

[Commentary]

(b) Responses to oral warnings over radio.

[Commentary]

(c) Infra-red signature.

[Commentary]

(d) Radar signature.

[Commentary]

(e) Electronic signature.

[Commentary]

(f) Identification modes and codes.

[Commentary]

(g) Number and formation of aircraft.

[Commentary]

(h) Altitude, speed, track, profile and other flight characteristics.

[Commentary]

(i) Pre-flight and in-flight air traffic control information regarding possible flights.

[Commentary]

  1. The feasibility of taking precautions often depends on the degree of threat presented by an unidentified aircraft, or by other factors. A potential threat can be more or less immediate. A potentially hostile aircraft that is approaching rapidly represents a greater threat than one traveling in another direction. Considerations of force protection suggest that greater precautions ought to be taken to verify that the aircraft constitutes a military objective when more time is reasonably available before a decision to engage it.

  2. An attacker must bear in mind that verification can be complicated by camouflage, stealth or deception designed to conceal the presence or military status of an enemy aircraft. Certain forms of deception would, however, amount to unlawful perfidy, see Section Q.

  3. Rule 40 applies to any type of aircraft, provided that it constitutes a military objective. As to civilian airliners, they are entitled to particular care in terms of precautions, see Section J (I) and J (III).

  4. The factors listed are provided by way of illustration, and their specific relevance depends on the factual background. There may be other factors relevant to verification, such as information based upon intelligence gathering. As well, it ought to be borne in mind that medical aircraft have specific means of identification, such as a flashing blue light and radio message (see Commentary on Rule 76 (b)).


Visual identification means that an aircraft is identified as a military objective by the use of eyesight, including the use of binoculars or similar sight-enhancing devices. This is typically achieved through interception of the aircraft (see the chapeau of the Commentary on Section U).

An unidentified aircraft ought to be raised on radio and asked to identify itself and state its intentions. The “response” can be either explicit or implicit, in which case it may be demonstrated by conduct such as change of course or any other manoeuvres. The response, or absence thereof, may strengthen or weaken conclusions as to the aircraft’s nature.

Infra-red signature means the appearance of the aircraft to infra-red sensors. It depends on several factors, including the temperature of the aircraft and the waveband of the detecting sensor.

Radar signature means (i) the detailed waveform of a radar echo from the aircraft; and (ii) the detailed characteristics of a radar transmission, i.e. an indication of what kind of radar the aircraft is using. The radar echo can give indications about the size, shape and movements of an aircraft, including moving parts such as the rotor of a helicopter.

Electronic signature means the detailed characteristics of the electronic emissions from the aircraft, which may reveal, e.g., the type of radio communication equipment used by the aircraft. The second definition of radar signature, as set forth in Rule 40 (d), may also be regarded as a form of electronic signature.

Identification modes and codes refer to systems whereby an aircraft that is detected on radar is interrogated by an electronic signal (also called secondary surveillance radar (SSR)) and gives an automatic response by using a transponder. The response ought to be used to identify the aircraft to both an intercepting aircraft and to airspace managers, whether military or civilian. Civilian systems are designed to assist the manage-ment of air traffic, while the purpose of military systems (also called Identification, Friend or Foe (IFF)) is to avoid the direction of attacks against friendly forces (“blue-on-blue”) or civilian aircraft. The fact that an aircraft identifies itself as either a friendly military aircraft or as a civilian aircraft is not necessarily conclusive evidence of its character.

Civilian aircraft will usually fly alone, while military aircraft may fly in formation depending on their mission. However, civilian aircraft are sometimes “escorted” by military aircraft in which case they may become a military objective (see paragraph 3 of the Commentary on Rule 27 (d)).

  1. Military aircraft on attack missions can make manoeuvres that civilian aircraft are not likely to do, such as approaching the target at low altitude in order to avoid or postpone detection by radar and thereafter making a sharp climb before launching weapons that require a minimum altitude.

  2. A steady course by an aircraft originating from one exclusively civilian airport and heading towards another, may suggest that it is a civilian aircraft.

  1. In some areas, civilian air traffic (including civilian airliners) may be frequent, whereas in other areas such traffic may be light. These factors must be taken into account when determining the nature of an aircraft.

  2. Information received from air traffic control services as to whether scheduled or non-scheduled flights can be expected around a particular location at a particular time ought to be taken into account, although the possibility that an aircraft is off schedule or off course ought to be considered.

Categories: G: Specifics of Attacks Directed at Aircraft in the Air Tags:

Rule 41

Belligerent Parties and Neutrals providing air traffic control service ought to establish procedures whereby military commanders – including commanders of military aircraft – are informed on a continuous basis of designated routes assigned to, and flight plans filed by, civilian aircraft in the area of hostilities (including information on communication channels, identification modes and codes, destination, passengers and cargo).

[Commentary]

  1. This Rule is based on Para. 74 of the SRM/ACS.[312]

  2. Rule 41 deals with general precautions whose purpose is to promote a clearer understanding of the situation in the air in a general sense, so that confusion and the likelihood of mistakes can be minimized. The feasible precautions mentioned in Rule 40 are specifically directed at clarifying the status of a particular flight.

  3. The extent to which Rule 41 can be applied in practice depends on the circumstances, especially the degree of air control exercised over the relevant airspace.

  4. States providing air traffic control services in their region bear a special responsibility for the safety of civilian air traffic.

  5. Neutrals providing air traffic control service ought to cooperate in establishing the necessary procedures, in the interest of the safety of civilian air traffic. However, under the law of neutrality, Neutrals must not appear to support military operations by Belligerent Parties (see Section X).

  6. If air traffic control services are operated by a private firm, all concerned parties ought to cooperate with the firm, as far as military requirements permit, in the interest of the safety of civilian aviation.

  7. In non-international armed conflicts, there is no such thing as neutrality in the legal sense, and Rule 41 is therefore not applicable. However, (i) the central government providing air traffic control services ought to behave in accordance with Rule 41; and (ii) when a foreign State conducts air traffic control services in an area subject to a non-international armed conflict, it ought to make its best efforts to contribute to the safety of civilian aviation in that area.

  8. In non-international armed conflicts, a national air traffic control service can hardly be expected to open channels of communication “on a continuous basis” with the commanders of non-State organized armed groups. All bodies providing air traffic control services, however, ought to do everything feasible to ensure that military commanders — including commanders of military aircraft — are made aware (to the maximum extent possible) of designated routes assigned to, or flight plans filed by, civilian aircraft in the area of military operations (including information on communication channels, identification modes and codes, destination, passengers and cargo).

  1. Para. 74 of SRM/ACS: “Belligerents and neutral States concerned, and authorities providing air traffic services, should establish procedures whereby commanders of warships and military aircraft are aware on a continuous basis of designated routes assigned to or flight plans filed by civil aircraft in the area of military operations, including information on communication channels, identification modes and codes, destination, passengers and cargo.”

Categories: G: Specifics of Attacks Directed at Aircraft in the Air Tags: