30 INTERNATIONAL LEGAL PROTECTION OF HUMAN RIGHTS IN ARMED CONFLICT peacekeeping operations. In this respect, the Secretary-General’s Bulletin mentioned above provides some guidance on the fundamental principles and rules of international humanitarian law which apply to United Nations forces actively engaged in armed conflict as combatants, to the extent and for the duration of their engagement. Moreover, it should be borne in mind that the Charter of the United Nations recognizes the protection and promotion of human rights as one of the fundamental principles of the Organization. In more general terms, military forces acting under the authority of the United Nations are expected to apply the highest standards in relation to the protection of civilians and are also expected to investigate and to ensure accountability for violations of international human rights and humanitarian law.