NATO-led peacekeepers have clashed with angry protesters in the north of Kosovo over a dispute regarding roadblocks that had been erected in the tense region.
At least three rioters and two alliance soldiers were injured in the clashes with Serb protesters on Friday.
The confrontation has raised tensions in the ethnic Serb-dominated area, where Kosovo Serbs had set up roadblocks to prevent the ethnic Albanian government in Pristina taking control of the border with Serbia.
The Serbs reject Kosovo's 2008 declaration of independence from Serbia.
The latest incident took place near the town of Zvecan, where NATO-led troops blocked a bridge using armoured vehicles and barbed wire as they moved to remove a roadblock.
Hundreds of protesters then started throwing rocks at the soldiers, with witnesses saying that troops responded by firing rubber bullets and tear gas. Some protesters fired back with handguns, they said.
NATO's mission in Kosovo, KFOR, said that two soldiers had been wounded in the incident and that one had been evacuated in a stable condition.
It did not say how the soldiers had been wounded.
"KFOR condemns this act of violence," NATO spokesman Colonel Uwe Nowitzky said. "KFOR will not allow the situation to escalate and will use a proportional level of force necessary to maintain a safe and secure environment."
KFOR said in a statement that it started removing the roadblocks to "improve freedom of movement" for both its troops and the citizens.
The statement said that the troops set up numerous temporary checkpoints and secured areas for safety reasons, and that the operation to remove roadblocks would continue.
Kosovan Serbs have vowed not to allow Kosovo's authorities to impose their rule in the north.
Dragisa Milovic, the mayor of Zvecan, told the Reuters news agency that KFOR had refused to allow Serb medical personnel to help wounded Serbs.
Milovic said: "A commander told me they have the authority to use deadly force on anyone who throws a stone or uses a weapon."
Milovic said he had asked Serbs to withdraw to restore calm.
Escalating tensions led to clashes last year that left dozens of NATO troops injured and posed an impediment to Serbia's bid for European Union membership.
EU officials have served as mediators in talks between Serbia and Kosovo.
Serbia refuses to acknowledge the independence of its former province. The new state of Kosovo has, however, been recognised by more than 80 countries, including the US and most EU countries.
Oliver Ivanovic, a Serbian government official dealing with Kosovo, criticised KFOR's decision to remove the roadblocks, saying it revives tensions amid efforts to revive the EU-mediated talks.
Ivanovic warned that "this is very dangerous and could escalate".
Serbia lost control over Kosovo after a war in 1998-99, which ended after NATO intervened militarily. About 10,000 people, mostly ethnic Albanians, were killed in the conflict.
Out of a population of about two million, there are some 120,000 ethnic Serbs in Kosovo, with 40,000 in the north on the border with Serbia and the rest scattered around the territory.