 Socialist Federal Republic of Yugoslavia was composed of six constituent republics : Bosnia @-@ Herzegovina , Croatia , Macedonia , Montenegro , Serbia , and Slovenia . In 1991 , Croatia , and Slovenia <unk> from Yugoslavia . Bosnia @-@ Herzegovina — a republic with a mixed population consisting of <unk> , Serbs , and Croats — followed suit in March 1992 in a highly controversial referendum , creating tension in the ethnic communities . Bosnian Serb militias , whose strategic goal was to secede from Bosnia and Herzegovina and unite with Serbia , <unk> Sarajevo with a siege force of 18 @,@ 000 stationed in the surrounding hills , from which they assaulted the city with weapons that included artillery , mortars , tanks , anti @-@ aircraft guns , heavy machine @-@ guns , rocket launchers , and aircraft bombs . From 2 May 1992 until the end of the war in 1996 , the city was blockaded . The Army of the Republic of Bosnia and Herzegovina , numbering roughly 40 @,@ 000 inside the besieged city , was poorly equipped and unable to break the siege . Meanwhile , throughout the country , thousands of predominantly <unk> civilians were driven from their homes in a process of ethnic cleansing . In Sarajevo , women and children attempting to buy food were frequently <unk> by Bosnian Serb sniper fire . 
