From May to December 1992, the Bosnian Ministry of the Interior (BiH MUP), Croatian Defence Council (HVO) and later the Bosnian Territorial Defence Forces (TO RBiH) operated the Čelebići prison camp. It was used to detain 700 Bosnian Serb prisoners of war arrested during military operations that were intended to de-block routes to Sarajevo and Mostar in May 1992 which had earlier been blocked by Serb forces. Of these 700 prisoners, 13 died while in captivity.
On 6 May 1992, Mate Boban met with Radovan Karadžić in Graz, Austria, where they reached an agreement for a ceasefire and discussed the details of the demarcation between a Croat and Serb territorial unit in Bosnia and Herzegovina.
On 15 May 1992, a JNA column was ambushed in Tuzla. 92nd Motorised JNA Brigade (stationed in "Husinska buna" barracks in Tuzla) received orders to leave the city of Tuzla and Bosnia-Herzegovina, and to enter Serbia.
The 1992 European Cup Final was a football match held on 20 May 1992 at Wembley Stadium, London, between Sampdoria of Italy and Barcelona of Spain. Barcelona won the game 1–0 after extra time, thanks to a Ronald Koeman free kick, to record their first triumph in the competition. It was the first to have a group stage involving the eight second-round winners split into two groups, and the winner of each one met in the final. In doing so, they became the second Spanish club to win the tournament and the 19th overall.
The Army of Republika Srpska was newly established and put under the command of General Ratko Mladić, in a new phase of the war. Shelling on Sarajevo on 24, 26, 28 and 29 May were attributed to Mladić by UN Secretary-General Boutros Boutros-Ghali.