A major BSA offensive started July 1993 that led to the fall of Trnovo and on 4 August 1993 Serb forces captured the Bjelašnica summit and part of the Igman supply road. The BSA advance was stopped under threat of NATO airstrikes. After tense negotiations the BSA retreated from the Bjelašnica summit, but not without blowing up the communications tower first. French United Nations Protection Force (UNPROFOR) units were stationed on Bjelašnica and the Igman area was declared a Demilitarized Zone (DMZ) by the UN.