Close to 1000 Serbs living in isolated villages among the majority Albanian communities in Kosovo have fled in the last three days as houses and churches were torched by Albanians despite a heavy presence of international peacekeepers.
US commander of NATO forces for Southern Europe, Admiral Gregory Johnson told reporters on Friday such attacks had to stop.
A total of 2000 French, British, German, Italian and US soldiers were rushed to Kosovo to reinforce the NATO-led multinational peacekeeping force KFOR, as ethnic violence continued for a third day.
Inter-ethnic violence broke out in the UN-administered province on Wednesday between minority Serbs and majority Albanians, leaving at least 31 people dead. It is the worst unrest since 1999 when Kosovo was placed under the world body's administration.
A 17th century mosque has been torched and other Islamic community centres attacked.
Serbian Prime Minister Vojislav Kostunica on Friday led tens of thousands of people in a mass protest in the capital Belgrade against the unrest in Kosovo.
Several other Serb leaders and church dignitaries joined the
Students of Belgrade University
protest in Belgrade
march, which passed off without incident as protesters filed through the city centre carrying banners reading "Stop the Genocide" and "Stop Killing Innocent Serbs".
Similar protests were reported in the northern Serbian town of Novi Sad, in Nis in the south and in Podgorica, the capital of Montenegro.
In the Serb-run part of Bosnia, more than 500 students and their professors held a peaceful protest against the flare-up of violence.
The Bosnian Serb government announced on Friday it was sending aid supplies to the Kosovo Serbs who have been forced from their homes by the outbreak of violence.
The violence erupted after a Serb teenager was shot and injured in a village south of Pristina on Monday and three Albanian children drowned after being chased into a river by Serbs in Mitrovica on Tuesday.
Places of worship have been
burnt to the ground in recent days
Meanwhile, a total of 61 NATO troops have been wounded, including three seriously, in bloody clashes, said a KFOR spokesman on Friday. He could not give details on the injuries nor the nationalities of those involved.
In the flashpoint town of Mitrovica, KFOR troops killed an alleged sniper.
Two explosions shook a quarter of Mitrovica predominantly inhabited by ethnic Albanians early on Friday, said an AFP correspondent on the scene.
The detonations occurred in the Little Bosnia quarter, an Albanian enclave in the predominantly Serb-inhabited northern part of the city.
KFOR soldiers threw a cordon around the quarter.
They were not able to say immediately what had caused the blasts.
Earlier in the day, residents of Mitrovica were startled by a loud blast. Peacekeeping troops later said it was a controlled explosion which they set off.
One of the KFOR soldiers said the blast had been set off intentionally, although it was not immediately clear what had been blown up, or why.