Frequently Asked Questions: IHL and the escalating conflict in the Middle East

International humanitarian law (IHL), also known as the “laws of war”, is the set of international rules that regulates armed conflicts, including the behaviour of States and other parties to conflict.

IHL is distinct from the body of international law that governs the legality of the resort to armed force between States which includes the United Nations (UN) Charter. 

IHL is multifaceted, comprised of different rules that regulate distinct aspects and situations arising in armed conflict. For example, it sets limits on how military operations can be carried out. Many of the rules governing the conduct of hostilities are anchored in the cardinal principles of distinction, proportionality, and precaution. Other sets of rules regulate how persons affected by armed conflict must be treated, including those who find themselves in the hands of a party to the conflict —for instance when they are detained or when they live under occupation. 

Three fundamental principles of IHL regulate the conduct of hostilities, i.e. the fighting between the parties to the conflict: distinction, proportionality and precautions. These are customary in nature and must be complied with in all circumstances by all parties - States, non-state armed groups and civilians taking a direct part in hostilities - in all armed conflicts - both international and non-international. Certain categories of persons and objects such as medical units, transports and personnel, objects indispensable to the survival of the civilian population and  installations containing dangerous forces, are afforded additional, heightened protection (see below question on the protection of civilian infrastructure). 

The principles and rules governing the conduct of hostilities apply whenever fighting takes place as part of an armed conflict: whether on land (ground operations), in the air (air warfare) or at sea (naval warfare), as well as in the cyber domain (cyber operations) and in outer space. 

The IHL principles and rules that govern the conduct of hostilities aim to protect the civilian population from the effects of hostilities. They do so by striking a balance between military necessity and humanity, imposing prohibitions and restrictions on the weapons, means and methods of warfare that parties to the conflict may use.

The principle of distinction requires that parties to the conflict must always distinguish between combatants and civilians, and between military objectives and civilian objects, such as homes, civilian infrastructure, and the environment. Parties may only direct their attacks against combatants, never against civilians; and they may only target military objectives, never civilian objects. Indiscriminate attacks, namely attacks that are not directed at specific military objectives as required, that cannot be so directed, or whose effects cannot be contained as required by international humanitarian law, are also strictly prohibited. Equally prohibited are acts or threats of violence the primary purpose of which is to spread terror among the civilian population, and the use of starvation of the civilian population as a method of warfare.

Attacks directed against a combatant or another military objective must respect the principle of proportionality. This means that it is prohibited to launch an attack that may be expected to cause incidental loss of civilian life, injury to civilians, and/or damage to civilian objects that would be excessive in relation to the concrete and direct military advantage anticipated. In other words, a military objective may be attacked only after an assessment leading to the conclusion that civilian losses and damage are not disproportionate to the military advantage foreseen.

The principle of precautions requires all parties to a conflict to take constant care to spare the civilian population and civilian objects from the effects of military operations. Given the significant risk of harm to civilians whenever executing an attack, IHL imposes detailed obligations to those planning, deciding on or carrying out attacks. In particular, all feasible precautions must be taken to

- Verify that targets are military objectives;
- Avoid, and in any event to minimize, incidental loss of civilian life, injury to civilians and damage to civilian objects;
- Assess whether the attack may be expected to violate the rule of proportionality;
- Cancel or suspend an attack if it becomes apparent that it would violate the principles of distinction or the rule of proportionality;
- Give effective advance warning of attacks which may affect the civilian population.

IHL also requires parties to the conflict to protect civilians and civilian objects under their control against the effects of attacks.  In cities, military and civilian people and objects are often intermingled. For parties involved in hostilities in urban or other populated areas, this intermingling presents important challenges, both militarily and in terms of avoiding civilian harm. Because urban warfare endangers civilians in specific ways, the protection afforded by the principles and rules of IHL is critical. 

Civilians and civilian objects are protected against attack and must not be targeted. IHL requires parties to armed conflict to always ensure their attack is directed against a specific military objective. This requires reasonable certainty as to the status of the target, as well as constant verification measures to achieve it. The targeting of people and objects requires an individual assessment in each and every case.

Insofar as persons are concerned, combatants (i.e., members of State armed forces – other than medical and religious personnel – and members of armed wings of non-State armed groups) may be targeted, unless they are hors de combat (wounded, sick, shipwrecked, incapacitated, have indicated a clear intention to surrender, or are otherwise in the power of the enemy). Civilians are protected against attack, unless and for such time only as they directly participate in hostilities. Political and administrative officials with no military status or command function are civilians and may not be targeted on the basis of their political or administrative function alone.

Insofar as objects are concerned, civilian objects are protected against attack and only military objectives may be targeted. These are objects that make an effective contribution to military action by their nature, location, purpose or use, and an attack on which offers a definite military advantage in the circumstances ruling at the time. In order to constitute a military objective, an object must be closely connected to the fighting. Objects that merely support the war effort, including financially, are not lawful targets. 

Infrastructure that enables the provision of essential services to civilians are in principle civilian objects, and as such are protected by all the IHL rules protecting the civilian population and civilian objects from the effects of hostilities. Importantly, this includes prohibitions against direct, indiscriminate and disproportionate attacks, and the rules on precautions in attack and  precautions against the effects of attack. (see above How does IHL protect civilians and civilian objects against the danger of hostilities?)

The services essential for the civilian population and other protected persons during armed conflict are interconnected and interdependent, which means the disruption of one can have domino or reverberating effects on others and result in multiple services being disrupted or even collapsing. For instance, electricity supply is needed to ensure the delivery of water and sanitation, solid waste disposal and the cold chain. Hospitals and food production and distribution capacities are then dependent on a reliable supply of safe water, sanitation, and electricity.

Attacks expected to damage critical infrastructure will likely affect a large part of the civilian population beyond the weapon's impact area and for a period well beyond the immediate aftermath of the attack. Such harm is relevant for both proportionality and precautions in attack insofar as it has a causal link to the attack and is reasonably foreseeable at the time of the attack.

IHL also affords special, heightened protection to certain types of critical infrastructure, notably hospitals and other medical facilities and transports, objects indispensable to the survival of the civilian population, and works and installations containing dangerous forces, in addition to cultural property and the natural environment. Pieces of energy infrastructure critical to the effective operation of other indispensable objects also enjoy special protection. Every special protection regime is different, but it often entails protection against operations other than attacks, and some degree of protection even in case such objects constitute military objectives.

Energy infrastructure, namely critical infrastructure that enables the provision of energy to civilians (such as networks of electricity-, fuel- and gas-related infrastructure) are also in principle civilian objects and as such may not be attacked. They become military objectives only if they make an effective contribution to military action (e.g., a power station providing electricity to a military barracks) and attacking them offers a definite military advantage in the circumstances. Sweeping or anticipatory classification of the entire electricity grid (or other energy network) of a country or area under enemy control as a military objective is prohibited. Moreover, IHL forbids attacks against pieces of energy infrastructure if the sole purpose is to degrade an adversary’s economic capacity, even if they are indirectly sustaining their war-fighting capability, to force the adversary to the negotiating table, to influence the will of the population, or to intimidate political leaders. 

In some cases, critical infrastructure (and other civilian objects) may be used simultaneously for both civilian and military purposes. Such so-called “dual-use” objects may become military objectives provided they meet the criteria required under IHL (see the definition of military objective above in How does IHL protect civilians and civilian objects against the danger of hostilities?). However, those planning and deciding to attack such infrastructure must take into account the incidental harm on civilians (including the impact on the civilian use of the object) that would result from the attack, take all feasible precautions to avoid or at least minimize it, and ensure that it is not excessive.

IHL imposes numerous prohibitions and restrictions on the development and use of specific weapons, under both treaty and customary law (see rules 70 to 86 of the ICRC customary IHL study). The use of all weapons, whether or not specifically restricted, must in any case comply with all the principles and rules governing the conduct of hostilities, including the prohibitions against direct, indiscriminate and disproportionate attacks, and the rules on precautions in attack (see above How does IHL protect civilians and civilian objects against the danger of hostilities?).

While there is no general prohibition under IHL against using heavy explosive weapons in populated areas, their use in such areas is very likely to have indiscriminate effects. This underpins the long-standing call by the ICRC and the broader International Red Cross and Red Crescent Movement to all States and non-state armed groups parties to armed conflicts to avoid the use of heavy explosive weapons in populated areas. These weapons should not be used in populated areas unless sufficient mitigation measures are taken to limit their wide area effects and the consequent risk of civilian harm.

90 states have now endorsed the 2022 Political Declaration on Strengthening the Protection of Civilians from the Humanitarian Consequences arising from the use of Explosive Weapons in Populated Areas . It is the first instrument of its kind committing States to, among others, review their military policy and practice and to restrict, or refrain as appropriate from the use of explosive weapons in populated areas, where such use may cause civilian harm. When properly implemented, it can contribute significantly to alleviating civilian suffering and strengthening respect for IHL.

With a view to reducing human suffering, the Arms Trade Treaty (ATT) prohibits State Parties from authorizing the export, transit and other transfers of conventional arms, ammunition and related parts and components covered under the Treaty in the knowledge that they would be used to commit war crimes or other international crimes (Art 6). The ATT also prohibits States Parties from exporting arms or other items covered by the Treaty  where there is an overriding risk that these could be used to commit or facilitate a serious violation of IHL or human rights(Art 7). Certain regional instruments also restrict arms transfers on humanitarian grounds and require such an assessment 

All States, even those not party to the ATT, have an obligation to refrain from transferring weapons to a party to an armed conflict where there is a clear risk that this would contribute to the commission of IHL violations. In addition, arms transferring States must do everything reasonably in their power to prevent and stop IHL violations committed by their arms trading partners (Art 1 common to the 1949 Geneva Conventions). States that supply weapons to a party to an ongoing armed conflict can be considered particularly influential in ensuring respect for IHL, owing to their ability to provide or withhold the means by which IHL violations may be committed. Conditioning, restricting or halting transfers of weapons are practical means in the power of arms transferring States to prevent and stop IHL violations.

Read more about arms transfers to parties to armed conflict.

While IHL does not explicitly prohibit or restrict the use of AI in military applications, it does restrict its development and use and places strict constraints on AI when it is integrated into weapon systems or used in some way to conduct warfare. As such, and like any new technology of warfare, AI must be capable of being used and must only be used in compliance with existing principles and rules of IHL (see above How does IHL protect civilians and civilian objects against the danger of hostilities?).

Against the backdrop of the growing development of and reliance on AI-related technologies in the military domain, it is important to recall that IHL obligations bind humans. It is humans who must ensure the lawfulness of attacks that they plan, decide upon or execute, and they remain accountable for those determinations. These assessments include whether attacks comply with the conduct of hostilities principles and rules, namely distinction, proportionality and precautions in attack, which cannot be outsourced to machines.

This does not mean that commanders and combatants cannot or should not use tools, including AI decision-support systems, to perform tasks such as collateral damage estimations or calculating the blast radius of munitions. However, such outputs should be understood as sources of information or computational indicators, rather than legal assessments of whether an attack complies with IHL. Accordingly, these systems and tools must be designed and used to support, rather than hinder or replace, human decision-making.

Read more about ICRC’s position on the use of AI in armed conflict.

Data centres used solely for civilian purposes, including those provided by private technology companies, are civilian objects. They must not be the object of attack.

Specific servers or data centres may be used to store data collected by armed forces, including intelligence, and data centres can provide the computing power needed to run AI models used by armed forces, or the digital space to host AI decision support systems. Whether and in which cases such data centres may become military objectives requires a case-by-case analysis. Unless and for such time as they qualify as a military objective they must not be attacked. Even if a specific data centre, or parts thereof, qualify as a military objective, the rules and principles of proportionality and precautions in attack must still be respected. Applying these principles and rules requires assessing both foreseeable direct and indirect civilian harm, such as harm to civilians working in the data centers, and harm to civilian populations reliant on the data centers for the proper functioning of essential services, and taking all feasible precautions to avoid and in any event minimize it. (see above How does IHL protect civilians and civilian objects against the danger of hostilities?)

IHL applies to the use of all means and methods of warfare, including cyber operations (also called ICT capabilities). This means that all parties to armed conflicts, including their cyber units, commands, or intelligence agencies, must respect the IHL principles and rules governing the conduct of hostilities when conducting cyber operations in the context of an armed conflict (see above How does IHL protect civilians and civilian objects against the danger of hostilities?). 

Civilian hackers that conduct their operations in the context of and associated with an armed conflict must also respect IHL, and may be criminally liable if committing grave violations of IHL (war crimes). Civilian hackers must, for example, not target civilian objects (institutions, infrastructure, businesses), medical facilities and humanitarian organizations, installations containing dangerous forces, or objects that are indispensable for the survival of the civilian population (e.g. agriculture, food production, water). 

States must take feasible measures to ensure respect for IHL by hackers operating on their territory. This includes making IHL known to civilian hackers, demanding civilian hackers to respect IHL and not encouraging them to violate it, and taking measures to suppress IHL violations, including legal, disciplinary, or administrative measures.

IHL grants both general and specific protection to the natural environment. The notion of the natural environment under IHL includes everything that exists or occurs naturally, such as the general hydrosphere, biosphere, geosphere and atmosphere (including fauna, flora, oceans and other bodies of water, soil and rocks). The natural environment is civilian in character, and is therefore protected by the principles of distinction, proportionality and precautions (see question above How does IHL protect civilians and civilian objects against the danger of hostilities?). This means, among other things, that attacks that may be expected to cause incidental damage to the natural environment that would be excessive in relation to the concrete and direct military advantage anticipated is prohibited. IHL also prohibits the use of methods or means of warfare that are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment. Destruction of the natural environment may not be used as a weapon. 

Naval warfare can cause harm both at sea and on land - from attacks on ships to damage affecting coastal communities. It can also put critical offshore infrastructure at risk, which makes strict respect for the rules of armed conflict essential. 

Fighting at sea is governed by international law applicable to armed conflict in the maritime domain. This framework consists of treaties and customary rules developed and evolving over time with the evolution of the maritime domain. It includes international humanitarian law (IHL) — notably the Second Geneva Convention protecting the wounded, sick, and shipwrecked at sea — alongside the law of the sea and maritime neutrality, among others. The 1994 San Remo Manual on naval warfare is widely recognized as a leading restatement of these rules.

No matter the battlefield, civilians, non-combatants, and civilian objects must be protected, including at sea. However, warfare at sea has its own realities, and the law reflects that with specific rules for certain means and methods of naval warfare such as on blockades, maritime exclusion zones, and other measures short of attack such as prize measures and contraband. 

As in all warfare, the right to choose means and methods of naval warfare is not unlimited. Weapons such as missiles, torpedoes, projectiles, and naval mines must be used in accordance with the principles and rules of distinction, proportionality, and precautions. (see above How does IHL protect civilians and civilian objects against the danger of hostilities?) Surface ships, submarines and aircraft are bound by the same rules, and so are weapons relying on emerging technologies such as uncrewed and autonomous maritime systems.

Merchant and other civilian vessels are always protected from attack unless they become military objectives, such as by carrying troops or directly supporting military operations or engaging in fighting. Even then, the rules of proportionality and precautions apply to minimize harm to crews, passengers, nearby vessels, offshore infrastructure, and the marine environment. 

Generally, the high seas freedom of maritime navigation continues to exist during armed conflict, and belligerents are obliged to consider the interests of neutral States and vessels in their maritime operations. For example, the rights of transit passage - and, where applicable, non-suspendable innocent passage - through straits used for international navigation, as well as the right of archipelagic sea lanes passage through archipelagic waters, provided under general international law continue to apply in times of armed conflict. Interference with neutral vessels is also subject to important legal constraints, notably in the context of maritime exclusion zones, contraband control, and naval mine warfare.

When neutral States respect their neutral status and their vessels avoid non-neutral service, the law of maritime neutrality can reduce the effects of armed conflict, with only limited grounds for belligerent interference. Neutral territory remains inviolable and hostile actions by armed forces in neutral waters and neutral airspace are prohibited in almost all circumstances. In carrying out operations in the economic exclusive zone of neutral States or other areas where they enjoy rights under international law, belligerents must have due regard for the rights and duties of those neutral States. 

Naval blockades, namely military operations to prevent the access or departure of all vessels to or from the enemy port or coasts, are legal only under strict rules: they must be declared, effective, and applied impartially. They cannot starve civilians or block humanitarian relief, and any civilian harm must not be disproportionate to the expected military advantage. They must not bar access to neutral ports or coasts. 

During armed conflict, the wounded, sick, or shipwrecked at sea must be protected and cared for without discrimination. The law requires rescue at sea and protects vessels engaged in rescue and medical care - recognizing that the ocean itself can be as deadly as the enemy. The dignity of those who die at sea due to hostilities must be respected. 

Under the Second Geneva Convention (GC II), warring parties must take all possible measures to search for and collect the wounded, sick, shipwrecked, and dead at sea after each engagement. IHL may not require the vessel conducting a long-range strike - or a submarine to surface - to immediately render assistance to casualties in every case. But it does, at a minimum, require them to consider alternative ways to facilitate rescue. For example, reporting the location of the incident to authorities, enemy or neutral vessels, or humanitarian actors capable of carrying out rescue operations. The protective purpose of GC II cannot be achieved without a good-faith interpretation of this duty. It is an obligation of conduct, carried out with due diligence and adapted to the specific context. Each organ of a party to the conflict must assess, in good faith, what measures are possible at its level.

In the harsh conditions of warfare at sea, neutral vessels or coastal rescue organizations may be the best or only means to ensure as many wounded, sick, shipwrecked, or dead persons as possible can be rescued or recovered. Depending on the situation, warring parties may be legally obliged to inform neutral vessels in the vicinity and appeal to their charity to take them on board and care for them.  Under the law of the sea and maritime law, neutral vessels may be obliged to engage in rescue. 

Parties to the conflict, as well as neutral states, are required to respect and protect wounded and sick and shipwrecked persons who enter their territory, to ensure that they receive the medical care required by their condition, and to take appropriate measures to search for, collect and identify the dead and missing. They must be treated humanely, protected from violence and intimidation, and provided with adequate food, medical care, and legal protections under international humanitarian law. The dead found at sea must also be collected and treated with dignity, and all relevant information collected to be able to identify them.

If neutral States intern shipwrecked combatants (due to how they interpret their obligations under the law of neutrality), they have to treat those persons as prisoners of war under the Third Geneva Convention. Shipwrecked merchant mariners should be released as soon as possible.  

Boarding, inspection, and seizure of vessels at sea can all lead to the detention of persons. Likewise, once the wounded, sick and shipwrecked are collected after an engagement, certain individuals among them might be identified for detention. Persons deprived of their liberty at sea are especially vulnerable and must therefore be held on ships only as a temporary measure, pending transfer to land at the earliest possible opportunity. They must be provided with good conditions of detention, properly registered, and afforded procedural safeguards.

The Third Geneva Convention sets out detailed protections for prisoners of war. Any member of the armed forces of a party to an international armed conflict, who has fallen into the power of the enemy by any means, is a prisoner of war. 

The status of prisoner of war also applies to members of other forces who fight on behalf of the State while fulfilling certain requirements to distinguish themselves from the civilian population. Militaries often deploy with authorized civilians alongside them, such as civilian staff, war correspondents, supply contractors, and others who accompany the armed forces without being member. They too are entitled to prisoner of war status, as are a few additional categories of people as set out in Article 4 of the Third Convention. Prisoner of war status does not depend on the nationality of the person.

Medical and religious personnel must be sent back to the party to which they belong, unless their retention is necessary to assist prisoners of war. If they are exceptionally retained on this basis, they are not prisoners of war but are entitled at minimum to the same benefits and protection as prisoners of war.

Read more about prisoners of war.

IHL protects anyone who is deprived of liberty in an international armed conflict, not only prisoners of war. This includes persons interned on security grounds, as well as those detained or convicted of criminal offences, whether or not the offences are related to the conflict. Certain fundamental guarantees, such as the prohibition of torture, apply regardless of the situation of the person or the nature of the deprivation of liberty. The application of other specific provisions may, however, depend on these factors.

Most provisions of the Fourth Geneva Convention apply to ‘protected persons’. This term is defined by the Convention and covers foreign nationals deprived of liberty by a party to the conflict, with some exceptions. The Convention sets out basic protections for protected persons in criminal detention, and detailed protections for protected persons who are ‘interned’. Internment is an exceptional form of deprivation of liberty without criminal process, permitted by the Convention when justified on the basis of serious threats to the security of the detaining State. The Convention explicitly prohibits States from interning protected persons except in accordance with its provisions.

Anyone who has engaged in hostilities but is outside the scope of prisoner of war status under Third Convention is protected by the Fourth Convention (assuming its nationality requirements are met). 

Anyone who neither qualifies as a prisoner of war under the Third Convention nor as a ‘protected person’ under the Fourth Convention (due to nationality requirements) remains protected by IHL. Such persons as well as any person deprived of liberty in relation to a non-international armed conflict, are covered by a range of rules of customary international humanitarian law, including fundamental guarantees such as the prohibitions of murder, torture and ill-treatment, and unfair trial, which are also reflected in Article 75 of the first Additional Protocol to the Conventions.

A person who qualifies as a ‘protected person’ under the Fourth Convention does not lose that status or the protection of the Convention if they engage in espionage, sabotage or other activities that pose similarly serious threats to security. However, the Convention exceptionally permits certain restrictions that would otherwise not be allowed, if justified in individual cases of this kind. (Where Additional Protocol I applies, in occupied territory such restrictions can only be applied in cases of espionage, not in cases of sabotage or other security threats.)

Any such restrictions must be necessary for the security of the State and primarily relate to communication of the person with the outside world. For instance, an internee would ordinarily be entitled to send and receive correspondence and to receive visits from family members, but these rights may be restricted in the case of a spy. However, the Convention explicitly prohibits the imposition of restrictions on an individual that would, on their own or cumulatively, amount to inhumane treatment or deprive the person of their rights of fair and regular trial.

Members of the armed forces who are captured while engaged in espionage do not have the right to prisoner-of-war status. They may not be convicted or sentenced without previous trial. They remain protected under the Fourth Convention (subject to the possible restrictions set out above), Article 75 of Additional Protocol I, or customary international humanitarian law.

Visits by the ICRC are exclusively humanitarian and follow working methods that include confidentiality. Accordingly, it is the ICRC’s view that notification of a person’s detention and the ICRC’s right to conduct visits to that person are not subject to restriction on the basis of the person being a spy or saboteur. Requirements under the Convention to collect and transmit information about all protected persons who are interned, placed in assigned residence, or kept in custody for more than two weeks, also continue to apply to spies and saboteurs.