Any violation of the laws of war , as laid down by international customary law and certain international treaties .
At the end of World War II, the part of the London Agreement signed by the U.S., Britain, the Soviet Union, and France established three categories of war crime: conventional war crimes (including murder, ill treatment, or deportation of the civilian population of occupied territories), crimes against peace, and crimes against humanity (political, racial, or religious persecution against any civilian population). The charter also provided for an international military tribunal to try major Axis war criminals. It further stated that a defendant's position as head of state would not free him from accountability, nor would having acted on orders or out of military necessity. German and Japanese war criminals were tried before Allied tribunals in Nürnberg and Tokyo in 194546 and 194648, respectively, and in the 1990s tribunals were created for the prosecution of war crimes committed in Rwanda and the territory of the former Yugoslavia. See also Geneva Convention ; genocide ; Hague Convention ; Nürnberg trial .