defied the 2008 Kosovo declaration of independence (the Kosovo Serb enclaves had been under local control, disputed by the Kosovar Albanian Assembly) until the 2013 Brussels Agreement. The government of the Republic of Kosovo sought to install customs officials at the administrative border crossings with Central Serbia. Because Kosovar Serbs opposed the presence of Kosovar Albanians at the crossings, they erected roadblocks to make movement difficult for KFOR personnel. Timeline July–August 2011 On 26 July 2011, during the operation to take control of the administrative border posts, a Serb sniper killed Enver Zymberi, a member of the Kosovo Police Special Intervention Unit. Twenty-five more policemen were wounded, with at least one being treated in hospital for severe wounds. The KFOR Mi-17 helicopter that had moved the 16 Kosovo special police personnel belonged to the Croatian Army. Later that day, the same helicopter had been fired at. An hour later, 14 new Kosovo police officers and three customs officers were located in Brnjak. Though the Kosovo police later withdrew and there was a lull in tensions, some Serbian protesters returned in the evening and attacked the post. Clashes continued on 27 July after armed Kosovar police took over two administrative border posts to enforce the writ of the central government in Pristina; ethnic Serbs burned down the administrative border post at Jarinje. The mob, which reportedly included "dozens of masked men, armed with crowbars, clubs, axes, Molotov cocktails and handheld flares," as well as rocks and other debris, were said to have attacked the NATO troops who were a part of KFOR operations. Reports also suggested the troops may have been fired upon. This was the same administrative border post that had been burned down in 2008 after Kosovo's unilateral declaration of independence. Following the intervention of KFOR's NATO troops, a NATO operations officer, Lieutenant Colonel Ralf Adametz, said "the situation is now under control, but tense". There was a thaw in tensions on 28 July, after all Kosovar units withdrew from North Kosovo, leaving KFOR's NATO troops in charge of maintaining peace in the region. In return, the Serbs removed most of the roadblocks they had created. KFOR took full control of the two crossings and General Erhard Bühler declared the area around the two crossings to be military areas, therefore giving shoot-at-sight orders to his soldiers for anyone crossing the area. As of 29 July, NATO units remained in