Serb extremists attacked three town halls in northern Kosovo and clashed with the troops of a NATO-led peacekeeping Kosovo Force, or KFOR, injuring 25 of its troops.

Iran PressEurope: KFOR condemned Monday’s violence, which erupted after ethnic Albanian mayors took office in northern Kosovo’s Serb-majority area following elections boycotted by the Serbs.

“While countering the most active fringes of the crowd, several soldiers of the Italian and Hungarian KFOR contingent were the subject of unprovoked attacks and sustained trauma wounds with fractures and burns due to the explosion of incendiary devices,” it said in a statement.

Kosovo President Vjosa Osmani accused her Serbian counterpart Aleksandar Vucic of destabilizing Kosovo.

“Serb illegal structures turned into criminal gangs have attacked Kosovo police, KFOR officers & journalists. Those who carry out Vucic’s orders to destabilize the north of Kosovo must face justice,” Osmani tweeted.

Vucic said that 52 Serbs were injured in the clashes, three of them seriously.

Clashes erupted earlier on Monday in Zvecan, one of the towns in north Kosovo, where state police – staffed entirely by ethnic Albanians after all Serbs quit the force last year – sprayed pepper gas to repel a crowd of Serb extremists who tried to force their way into the municipality building, witnesses said.

Serb protesters threw tear gas and stun grenades at NATO soldiers, according to the Reuters news agency.

In Leposavic, close to the border with Serbia, US peacekeeping troops in anti-riot gear placed barbed wire around the municipality building to protect it from hundreds of angry Serbs gathering nearby.

Serbs, who form a majority in Kosovo’s north, have never accepted its 2008 declaration of independence from Serbia and still see Belgrade as their capital more than 20 years after the Kosovo Albanian uprising against repressive Serbian rule.

In April this year, Serbs refused to take part in local elections, and ethnic Albanian candidates won the mayoral races in four Serb-majority municipalities with a 3.5 percent turnout.