Around 25 NATO peacekeeping soldiers defending three town halls in northern Kosovo were injured in clashes with Serb protesters on Monday.

Serbian President Aleksandar Vucic said that 52 Serbs were injured, three of them seriously, accusing Kosovo Prime Minister Albin Kurti of creating tensions.

Vucic called on Serbs in Kosovo to avoid clashes with NATO soldiers.

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

KFOR, the NATO-led peacekeeping mission to Kosovo, condemned the violence.

"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.

7 Hungarian soldiers were seriously injured and will be taken to Hungary for treatment, according to Hungary's Defense Minister Kristof Szalay-Bobrovniczky, adding that 20 soldiers were injured.

Italian soldiers were also among the injured peacekeeping troops.

The tense situation developed after ethnic Albanian mayors took office in northern Kosovo's Serb majority area after April elections the Serbs boycotted - a move that led the U.S. and its allies to rebuke Pristina on Friday.

In Zvecan, one of the towns, Kosovo police - staffed by ethnic Albanians after Serbs quit the force last year - sprayed pepper gas to repel a crowd of Serbs who broke through a security barricade and tried to force their way into the municipality building, witnesses said.

Vucic, who is the commander-in-chief of the Serbian armed forces, raised the army's combat readiness to the highest level, Defense Minister Milos Vucevic told reporters.

"This implies that immediately before 2:00 p.m. (1200 GMT), the Serbian Armed Forces' Chief of the General Staff issued additional instructions for the deployment of the army's units in specific, designated positions," Vucevic said, without elaborating.

NATO peacekeepers also blocked off the town hall in Zubin Potok to protect it from angry local Serbs, witnesses said.

Igor Simic, deputy head of the Serb List, the biggest Belgrade-backed Kosovo Serb party, accused Kosovo Prime Minister Albin Kurti of fueling tensions in the north.

"We are interested in peace. Albanians who live here are interested in peace, and only he (Kurti) wants to make chaos," Simic told reporters in Zvecan.