Police in Kosovo have clashed with ethnic Serbs during raids over suspected good smuggling.
At least six police officers and one Serb civilian were injured on Wednesday, the authorities said.
Eight people were arrested, police added in a statement, saying that the raid was over and the situation is now calm.
But the incident has heightened tensions in the western Balkans and led to calls for calm from the wider international community.
The NATO-led international peacekeeping force in Kosovo (KFOR) has urged both sides to prevent "wider chaos".
Relations between Kosovo and Serbia are already high after a recent border dispute over vehicle license plates threatened to spiral into violence.
According to Kosovo police, officers carried out raids in four areas on Wednesday, including northern Mitrovica which is mostly populated by ethnic Serbs.
Video footage showed police firing tear gas as ethnic Serbs hurled stones and other objects at officers.
Police said that "criminal groups gathered in an organised way to block roads with vehicles, used liquid gas tanks, stun bombs, shot with weapons and hand grenades".
The civilians are accused of "hampering and attacking custom and police officials committing their duty."
At least seven people were injured in the clashes, including a 36-year-old ethnic Serb.
Petar Petković, a Serbian government official in charge of Kosovo talks, said the man was shot in the back. Doctors were working to remove the bullet that had ended up in his lungs, Petković added.
Kosovar media has reported that a police car and at least two other cars with Kosovo licence plates were burned.
Meanwhile, Serbian media have reported an "extremely tense" atmosphere in the region after Kosovo police raided a pharmacy and other shops in an apparent attempt to stop the smuggling of goods.
Kosovo's Prime Minister has called on ethnic Serbs "not to fall prey" to certain Serbian media that he says are politicising a police raid.
"Crime and criminals groupings will not be tolerated and will be fought. We shall fight and prevent smuggling," Kurti wrote on Facebook.
But Serbian Prime Minister Ana Brnabić has demanded a "quick reaction" from the “international community" as the situation in Mitrovica is "more than dramatic".
"This kind of conduct ... brings us to the edge of chaos," Brnabic said in a statement.
Serbian President Aleksandar Vucic is also heading to the town of Raska near Kosovo to hold a meeting with Kosovo Serb representatives.
EU foreign policy chief Josep Borrell said Brussels was “in contact with Belgrade and Pristina" adding that "all open issues must be addressed through the EU-facilitated dialogue."
"The violent incidents in the north of Kosovo need to stop immediately," Borrell said on Twitter.
"Unilateral and uncoordinated actions that endanger stability are unacceptable."
Serbia has refused to recognise Kosovo's declaration of independence in 2008, following a deadly 1998-99 war between Serb troops and ethnic Albanians.
On Tuesday, a court in Kosovo separately ordered for five suspects to be held in pre-trial detention as part of a months-long investigation into a cache of weapons and explosives.
Prosecutors said in a statement the five detainees were planning to commit attacks against Kosovo’s "constitutional order".
A police raid over the weekend had uncovered an anti-tank rocket launcher, assault rifles, ammunition, rockets, and other explosive equipment.