( dpa )- The UN Mission in Kosovo (UNMIK) chief, Joachim Ruecker, on Friday ordered police to "restore law and order" after hundreds of Serb protesters stormed a court building in the hotspot town Mitrovica.
The incident occurred as the NATO Secretary General Jaap de Hoop Scheffer arrived in Kosovo for his first visit since the province declared independence from Serbia on February 17.
De Hoop Scheffer met top Kosovo officials commanders of the NATO peacekeeping mission in Kosovo, the Kfor. Kosovo Serb officials however refused to talk to him.
Earlier in Mitrovica, some 300 protesters broke through an international police cordon in the northern, Serb-dominated section of the divided Mitrovica and broke into the UN municipal court building, Kosovo police said.
"Those who turned to violence crossed one of UNMIK's red lines. This is completely unacceptable. I have instructed UNMIK Police to restore law and order," Ruecker said after meeting Prime Minister Hashim Thaci and President Fatmir Sejdiu.
Thaci and Sejdiu had called on the UN, which has governed Kosovo since NATO drove Serbian security forces out in 1999, to assert its authority in Mitrovica, where Serbs have been protesting daily since Pristina declared independence from Serbia a month ago.
EU President Slovenia also condemned the attack on the court in Mitrovica. The EU has sent a law-enforcing mission of nearly 2,000 experts to Kosovo to help it along its first independent steps.
"We strongly condemn the attack on UNMIK personnel and the seizure of the court in north Mitrovica," Ljubljana's Ambassador Vojko Volk said in a statement.
Serbs are a majority in northern Mitrovica and make up about a fifth of the population north of the town, while Albanians make up the overwhelming majority in the rest of Kosovo.
Raised tensions persist in northern Kosovo where Serbia has established parallel structures of authority in a bid to impose a partition of Kosovo along ethnic lines. Belgrade has nodded approvingly even at the violent protests of last month. Nobody was injured in Friday's incident, but after forcing the police to retreat, the crowd remained in the building, took down the UN flag and put up a Serbian flag, police spokesman Besim Hoti said.
The standoff continued into the evening. Serbian media reported that some 50 Kosovo Serbs who worked in the court prior to the arrival of NATO and UN remained in the building, with a UN riot police deployed nearby.
De Hoop Scheffer described the incident as a "provocation" and an "act against UN, against the world's community," but said it was an issue for police, not the military.
"I think this is not a matter for KFOR, but for the UN, and every action should be taken by UNMIK," he told a press conference ahead of departure from Pristina. "KFOR is not a police force ... this is a police matter, this is against law and order,"
NATO, which maintains some 17,000 peacekeepers in Kosovo, as well as the international UN police and Kosovo police, have kept a low profile amid protests and riots over the past month.