International humanitarian law
International humanitarian law, according to the International Committee of the Red Cross, is a set of rules which seek, for humanitarian reasons, to limit the effects of armed conflict. Conflict includes conventional warfare between overt forces (jus in bello), the conduct of occupation forces, the conduct and treatment of prisoners of war and persons in occupied countries (i.e., jus post bello), and, with considerable argument, terrorism and guerrilla warfare.
It is part of the broader body of international law, defined in treaties and in customary international practice. International humanitarian law, however, does not determine the conditions under which the initiation of force is acceptable (i.e., jus ad bellum).