Yugoslav forces committed a series of atrocities in Kosovo . To prevent ethnic cleansing , the North Atlantic Treaty Organization ( NATO ) under the leadership of the United States began an air campaign called Operation Allied Force against Yugoslav military forces and positions and suspected Serbian paramilitaries . The air attacks against Belgrade by NATO were the first attacks on the city since World War II . Some of the worst massacres against civilian Albanians by Serbian forces occurred after NATO started its bombing of Yugoslavia . The Serbian police and paramilitaries also committed massacres during the war , including the Cuska massacre and the Podujevo massacre . NATO promised to end its bombings of Yugoslavia , when Milošević agreed to withdraw all Yugoslav and Serb security forces from Kosovo . After an array of bombings , Milošević submitted and recalled all forces , and NATO peacekeepers entered Kosovo
Podujevo massacre
Podujevo massacre
Serbia and Montenegro