War crimes are serious violations of international humanitarian law that can be committed in the course of armed conflict. They are punishable by both domestic and international tribunals. They include acts of murder, extermination, enslavement, imprisonment or deportation or forcible transfer of population, torture, grave forms of sexual violence and cruel treatment.
In the past, armies regularly behaved brutally to their enemies and civilians during armed conflict and whether they were punished depended on who won the war. At the end of World War II the murder of millions of Jews by the Nazis and the mistreatment of prisoners of war by the Japanese led to a change in attitudes. The victors of World War II made a commitment to prosecute anyone they suspected of war crimes and the UN established four different treaties and conventions that became known as the laws of war.
These treaties are a significant body of international law that defines what is permissible in armed conflict and limits the means and extent of violence that can be used by belligerent nations during war. They are also designed to limit the extent of harm that can be done to civilians and property.
The law of war was further developed by subsequent international conferences including the Hague Rules for War at Sea of 1899, the Geneva Conventions of 1907, the First Geneva Convention Relating to the Amelioration of the Condition of Wounded and Sick Members of Armed Forces at War of 1929 and the Fourth Geneva Convention of 1949. These conventions and their Additional Protocols form the core of international humanitarian law, which has been further developed by customary international law, human rights law, and the 1998 Rome Statute of the International Criminal Court.