soldiers were then deployed under the UN banner to monitor Macedonia's northern borders with the Republic of Serbia. Macedonia's first president, Kiro Gligorov, maintained good relations with Belgrade and the other breakaway republics and there have to date been no problems between Macedonian and Serbian border police even though small pockets of Kosovo and the Preševo valley complete the northern reaches of the historical region known as Macedonia (Prohor Pčinjski part), which would otherwise create a border dispute if ever Macedonian nationalism should resurface (see VMRO). This was despite the fact that the Yugoslav Army refused to abandon its military infrastructure on the top of the Straža Mountain up to the year 2000. As a result of the conflict, the United Nations Security Council unanimously adopted UN Security Council Resolution 721 on 27 November 1991, which paved the way to the establishment of peacekeeping operations in Yugoslavia. In Bosnia and Herzegovina in November 1991, the Bosnian Serbs held a referendum which resulted in an overwhelming vote in favour of forming a Serbian republic within the borders of Bosnia and Herzegovina and staying in a common state with Serbia and Montenegro. On 9 January 1992, the self-proclaimed Bosnian Serb assembly proclaimed a separate "Republic of the Serb people of Bosnia and Herzegovina". The referendum and creation of SARs were proclaimed unconstitutional by the government of Bosnia and Herzegovina and declared illegal and invalid. In February–March 1992, the government held a national referendum on Bosnian independence from Yugoslavia. That referendum was in turn declared contrary to the BiH and the Federal constitution by the federal Constitutional Court in Belgrade and the newly established Bosnian Serb government. The referendum was largely boycotted by the Bosnian Serbs. The Federal court in Belgrade did not decide on the matter of the referendum of the Bosnian Serbs. The turnout was somewhere between 64 and 67% and 98% of the voters voted for independence. It was not clear what the two-thirds majority requirement actually meant and whether it was satisfied. The republic's government declared its independence on 5 April, and the Serbs immediately declared the independence of Republika Srpska. The war in Bosnia followed shortly thereafter. Timeline Various dates are considered the end of the Socialist Federal Republic of Yugoslavia: 25 June 1991, when Croatia and Slovenia declared independence 8 September 1991: following a referendum the Republic of Macedonia declared independence which was ratified by the Assembly