STORY: Loud bangs echoed through the air as Serbian protesters clashed with NATO peacekeeping soldiers on Monday in the town of Zvecan in Kosovo.
About 25 soldiers were injured while defending its town hall as well as those in two other locations, the NATO-led mission said.
It condemned the violence.
Two Serbs were also injured, according to Serbian state TV.
The tense situation developed after ethnic Albanian mayors took office in northern Kosovo's Serb majority area.
The U.S. and its allies, which have strongly backed the country's independence, rebuked Kosovo for the move last week.
Serbs boycotted the local elections and some saw a turnout of 3.5%.
The Serbs are demanding that the Kosovo government remove ethnic Albanian mayors from town halls and allow local administrations financed by Belgrade to resume their work.
Serbia’s President Aleksandar Vucic put the army on the highest level of alert while urging Serbs in Kosovo not to get entangled in conflict.
"I am urging the Serbs in Kosovo, (and) I know how they feel and how difficult it is for them, not to get into a conflict with NATO...."
Kosovo’s president has accused Vucic of destabilizing the country.
But Igor Simic -- the deputy head of the biggest Belgrade-backed Kosovo Serb party -- says it's actually the other way around.
He accused Kosovo’s prime minister of stoking the chaos.
"Serbs do not have problems with Albanians,” he said.
Ethnic Albanians make up more than 90% of the population in Kosovo as a whole... but Serbs comprise a majority in the north.
They’ve never accepted its 2008 declaration of independence from Serbia, and still see Belgrade as their capital more than two decades after the Kosovo Albanian uprising against repressive Serbian rule.