International humanitarian law and other legal regimes are complementary in armed conflicts. They are, however, distinct and separate, especially "jus in bello" (or IHL), which regulates the way war is conducted and "jus ad bellum", which covers the reasons for war. Human rights and refugee law can overlap with IHL.
Both international humanitarian law and human rights law aim to protect the life, health and dignity of human beings. Whereas IHL applies only in times of armed conflict, human rights law applies at all times, in peace and in war.
States are required to take action to ensure respect for and application of both bodies of law. There are certain conditions under which some human rights can be suspended by a State if it faces a serious public threat. States cannot, however, suspend what are called hard-core human rights that are regarded as fundamental.
There are no provisions under IHL that allow a States to waive its application. IHL must be respected in all circumstances.
International refugee law protects and assists people who have crossed an international frontier. It is complementary to human rights law, and if the refugees are in an area of armed conflict, to IHL as well.
IHL is based on the 1949 Geneva Conventions and their Additional Protocols, the Hague Conventions and a series of treaties covering the means and methods of warfare, particularly weapons. The ICRC has a mandate of guardianship under the Geneva Conventions to promote respect and application of IHL.
Human rights law has been developed through a variety of international instruments. Those include the 1948 Universal Declaration of Human Rights, the 1966 Covenant on Economic, Social and Cultural Rights and the 1966 Covenant on Civil and Political Rights. Implementation mechanisms were established both at universal and regional levels.
Refugee law has its origins in the 1951 Convention Relating to the Status of Refugees. International supervision is the responsibility of the Office of the United Nations High Commissioner for Refugees (UNHCR).
IHL (jus in bello) is also distinct from the law establishing the prohibition of the use of force between States and defining exceptions to this principle (jus ad bellum). Jus ad bellum is governed by the UN Charter and implemented through UN mechanisms.
The obligation on States to respect and ensure respect for IHL is unaffected by arguments about the justification or prevention of armed conflict covered by jus ad bellum.