European Union and NATO forces have ordered additional troops to Mitrovica, the ethnically-split town in northern Kosovo, after a fresh spurt of violence between Serbs and Albanians over the weekend.
Following an explosion that hit a number of cars near a Serbian bar in the town, local Serbs set fire to two Albanian-owned shops, according to police.
In a second explosion, seven firefighters were injured when a grenade was apparently thrown while they were attempting to put out the fires.
The EU's EULEX mission to Kosovo and NATO's KFOR responded to the increased violence by boosting troop numbers in the Bosnjacka Mahala quarter of the town, the Albanian neighbourhood where the firefighters were attacked.
The two forces issued a statement calling on both sides to "stay calm."
They urged "all people of Mitrovica and from all other areas of Kosovo to stay calm and to stop all violent actions," according to AFP.
The missions also warned that they were ready to respond should there be a repeat of the violence.
"To any kind of threat to the safe and secure environment and the freedom of movement, KFOR and EULEX are ready to respond in a strong way," the statement said.
The troop movement follows another NATO re-deployment last week after a Serb teenager was stabbed by Albanians. Following the assault, a large group of Serbs then burnt several shops and attacked cars with Kosovo licence plates.
The Serbian minister responsible for Kosovo, Goran Bogdanovic, demanded NATO, UN and EU forces to "prevent provocations and escalation of conflict by Albanians."
"The violence we have seen in the past days is unacceptable," he told reporters. "Albanian politicians have to understand that it is not in anyone's interest to further destabilise [Kosovo],"
Serbians living in Mitrovica and elsewhere in Kosovo reject governance from the capital, Pristina, and maintain that they remain Serbian citizens.
Kosovar President Fatmir Sejdiu meanwhile on Sunday said people should "avoid provocation and help law and order forces to maintain stability."
Serbian President Boris Tadic on Friday said that the events proved Kosovo cannot enter the EU as a separate country.
"I am convinced that Kosovo has no future in the EU as an independent state, but only as Serbia's province," he told the FoNet news agency, adding that human rights for Serbs and other non-Albanians are not respected in Kosovo.