International humanitarian law is a set of rules which seek, for humanitarian reasons, to limit the effects of armed conflict. It protects longer participating in the hostilities and restricts the means and methods of warfare. The law is also known as the law of war or the law of armed conflict and it is part of the international law, which is the body of rules governing relations between States.

International law is contained in agreements between States, treaties or conventions, in customary rules, which consist of State practice considered by them as legally binding, and in general principles. International humanitarian law applies to armed conflicts. It does not regulate whether a State may actually use force; this is governed by an important, but distinct, part of international law set out in the United Nations Charter.

International humanitarian law is rooted in the rules of ancient civilizations and religions; warfare has always been subject to certain principles and customs. Universal codification of international humanitarian law began in the nineteenth century. Since then, States have agreed to a series of practical rules, based on the bitter experience of modern warfare. These rules strike a careful balance between humanitarian concerns and the military requirements of States.

As the international community has grown, an increasing number of States have contributed to the development of those rules. International humanitarian law forms today a universal body of law.

A major part of international humanitarian law is contained in the four Geneva Conventions of 1949. Nearly every State in the world has agreed to be bound by them. The Conventions have been developed and supplemented by two further agreements: the Additional Protocols of 1977 relating to the protection of victims of armed conflicts
Other agreements prohibit the use of certain weapons and military tactics and protect certain categories of people and goods.

These agreements include:

  •     The 1954 Convention for the Protection of Cultural Property in the Event of Armed Conflict, plus its two protocols;
  •    The 1972 Biological Weapons Convention;
  •    The 1980 Conventional Weapons Convention and its five protocols;
  •    The 1993 Chemical Weapons Convention;
  •    The 1997 Ottawa Convention on anti-personnel mines;
  •    The 2000 Optional Protocol to the Convention on the Rights of the Child on the involvement of children in armed conflict.

Many provisions of international humanitarian law are now accepted as customary law, that is, as general rules by which all States are bound
International humanitarian law applies only to armed conflict; it does not cover internal tensions or disturbances such as isolated acts of violence. The law applies only once a conflict has begun, and then equally to all sides regardless of who started the fighting. International humanitarian law distinguishes between international and non-international armed conflict
International armed conflicts: are those in which at least two States are involved. They are subject to a wide range of rules, including those set out in the four Geneva Conventions and Additional Protocol I.

Non-international armed conflicts are those restricted to the territory of a single State, involving either regular armed forces fighting groups of armed dissidents, or armed groups fighting each other. A more limited range of rules apply to internal armed conflicts and are laid down in Article 3 common to the four Geneva Conventions as well as in Additional Protocol II.

It is important to differentiate between international humanitarian law and human rights law. While some of their rules are similar, these two bodies of law have developed separately and are contained in different treaties. In particular, human rights law – unlike international humanitarian law applies in peacetime, and many of its provisions may be suspended during an armed conflict.

International humanitarian law covers two areas:
The protection of those who are not, or no longer, taking part in fighting;! restrictions on the means of warfare – in particular weapons – and the methods of warfare, such as military tactics.
International humanitarian law protects those who do not take part in the fighting, such as civilians and medical and religious military personnel. It also protects those who have ceased to take part, such as wounded, shipwrecked and sick combatants, and prisoners of war. These categories of person are entitled to respect for their lives and for their physical and mental integrity. They also enjoy legal guarantees.

They must be protected and treated humanely in all circumstances, with no adverse distinction. More specifically: it is forbidden to kill or wound an enemy who surrenders or is unable to fight; the sick and wounded must be collected and cared for by the party in whose power they find themselves. Medical personnel, supplies, hospitals and ambulances must all be protected.

There are also detailed rules governing the conditions of detention for prisoners of war and the way in which civilians are to be treated when under the authority of an enemy power. This includes the provision of food, shelter and medical care, and the right to exchange messages with their families