International humanitarian law applies in armed conflicts and seeks to restrict suffering and unnecessary damage. It can be applied to all armed conflict, regardless of the legitimacy of the use of force or its cause.

International humanitarian law lays down particular obligations for the parties to the conflict:

• The Four Geneva Conventions and Additional Protocols protect persons who are not participating in the hostilities or who are no longer combatants. Civilians, prisoners and other vulnerable persons must not be mistreated and the wounded must be cared for.
• International humanitarian law restricts the means and methods of warfare. Most of the rules of international humanitarian law are regulated in the First Additional Protocol of 1977, the Hague Convention of 1907 and in the 1980 Conventional Weapons Convention and its five protocols.

• Civilians and civilian objects may not be attacked in any circumstances. At all times, parties to the conflict must distinguish between “military targets” and civilians and civilian objects.
• Attacks on military targets are prohibited if they are likely to involve superfluous or unnecessary casualties among the civilian population or excessive damage to civilian objects or the environment. When attacking, the parties to the conflict must take all possible precautions to protect the civilian population and civilian property.
• It is prohibited to use civilians as protective shields.
• It is prohibited to misuse the emblems of the Geneva Convention.
• Weapons that cause unnecessary suffering of severe damage to the environment are prohibited. This includes e.g. biological and chemical weapons, anti-personnel mines and incendiary bombs and bullets.

In the event of an armed conflict or occupation all parties to the conflict, whether states or non state armed groups, must observe International Humanitarian Law:

• Armed conflicts between states (international armed conflicts) are subject to the rules set out in the four Geneva Conventions, Additional Protocol I of 1977 and the Hague Convention of 1907.
• A more limited range of rules apply to armed conflicts restricted to the territory of a single state as laid down in Article 3 common to the four Geneva Conventions and Additional Protocol II of 1977.

In addition, numerous rules of customary law apply in internal and international armed conflicts.

All individuals participating in armed conflict must comply with international humanitarian law. As a rule, severe violations of humanitarian international law are war crimes. Examples of war crimes include:

• torture and inhumane treatment of captives
• rape
• attacks on the civilian population
• unlawful expulsion of the civilian population
• taking of hostages
• deployment of children as soldiers

In the event of severe violations of the Geneva Conventions, every state has a duty

• to prosecute the suspected perpetrators or
• to hand them over to another state or an international criminal court for prosecution.