An explosion killed one person and injured 10 today in the Serb part of the divided town of Mitrovica in northern Kosovo, police and doctors said.
The explosion occurred just metres away from some 600 Serbs protesting against the opening of an administrative office which they see as representing the Albanian majority, northern Mitrovica police chief Milija Milosevic said.
Kosovo's Serb minority, financially backed by Serbia, refuses to accept Kosovo's independence, declared in 2008.
Serbs in northern Mitrovica said the perpetrator was an ethnic Albanian. Serb head of the Mitrovica region, Radenko Nedeljkovic, blamed the incident on the NATO and EU mission for not securing the protest.
Serbia's president, Boris Tadic, called an emergency session of the Security Council to discuss the tensions in the region.
"Serbia is once again facing huge challenges in Kosovo. Our citizens in Kosovo were attacked," Tadic said today.
Police said they believed the explosive device may have been a hand grenade. Police and doctors in Mitrovica had earlier said that 12 people were injured.
Kosovo president Fatmir Sejdiu condemned the attack and urged local and international institutions to help bring the perpetrators to justice.
Two years after Kosovo seceded from Serbia, the Ibar river still divides Mitrovica between Albanians in the south and Serbs in the north and tensions remain high.
Some 20,000 Serbs live in north Mitrovica. They refuse to deal with Kosovo institutions and see Belgrade as their capital.
In May, Nato peacekeepers and police had to intervene to separate thousands of Serbs and Albanians who clashed over the Belgrade-organised local election in the north.
Belgrade effectively lost control its province of Kosovo in 1999 when Nato intervened to halt the ethnic cleansing of Albanian civilians and the United Nations took over.
The fragile peace in Kosovo is kept by 10,000 Nato peacekeepers along with European Union police and justice missions.
Reuters