Largest peacekeeping force deployed on one operation

The United Nations peacekeeping mission with the largest deployment was United Nations Protection Force (UNPROFOR) that took place in former Yugoslavia from February 1992 to March 1995. The mission reached a strength of 39,922 military personnel in September 1994, including a 'Rapid Reaction Force'. Serious fighting in Croatia began in June 1991 when that Republic and its northern neighbour, Slovenia, declared themselves independent from Yugoslavia, and Serbs living in Croatia, supported by the Yugoslav People's Army, opposed this move. Efforts by the European Community to stop the hostilities in mid-1991 and to resolve the crisis in the framework of the Conference on Yugoslavia had proved unsuccessful.

Initially established in Croatia to ensure the demilitarisation of designated areas, UNPROFOR’s mandate was later extended to Bosnia and Herzogovina to support the delivery of humanitarian relief, and to monitor 'no fly areas' and 'safe areas'. It was subsequently further extended to the Former Republic of Macedonia for preventive monitoring in border areas.