Both Kosovo and Bosnia were part of the former Yugoslavia, which began to break up in 1991. The Bosnian War was an international armed conflict that took place between Bosnia and Herzegovina. The main belligerents were the forces of the Herzegovina and those of the self-proclaimed Bosnian Serb and Bosnian Croat entities within Bosnia and Herzegovina, Republika Srpska and Herzeg-Bosnia, which were led and supplied by Serbia and Croatia. The Kosovo War was an armed conflict in Kosovo that started in late February 1998 and lasted until 11 June 1999. It was fought by the forces of the Federal Republic of Yugoslavia (i.e. Serbia and Montenegro), which controlled Kosovo before the war, and the Kosovo Albanian rebel group known as the Kosovo Liberation Army (KLA), with air support from the North Atlantic Treaty Organization (NATO), and ground support from the Albanian army.