Dozens of NATO troops secured on Tuesday a municipal building in the Kosovo town of Zvecan, where the previous day 30 NATO soldiers and 52 Serb protesters were injured in clashes. Several ethnic Serbs gathered in front of the building but the situation was calm, a Reuters reporter said, as soldiers from the United States, Italy and Poland stood by in anti-riot gear. On Monday, Serb protesters in Zvecan threw tear gas and stun grenades at NATO soldiers. The NATO force, known as KFOR, said 30 of its soldiers were hurt in the clashes. Serbian President Aleksandar Vucic said 52 Serbs were injured. In another Serb-majority town, Leposavic, an ethnic Albanian mayor was unable to leave his office for more than 24 hours because of protesters outside, media reported. EU Foreign Policy Chief Josep Borrell condemned Monday’s violence “in the strongest possible terms”. “The violent acts committed against @NATO_KFOR troops, media, civilians and police are absolutely unacceptable,” Borrell said on Twitter. Tensions have risen since ethnic Albanian mayors took office in northern Kosovo’s Serb-majority area after elections the Serbs boycotted. Kosovo authorities have blamed Vucic for destabilising Kosovo. Vucic blamed Kosovo authorities for causing problem by insisting on installing new mayors.