The main bridge linking the Albanian and Serb communities in Kosovo's most volatile city was deserted yesterday as an international group cautioned that the area was in danger of becoming a long-term “frozen conflict”.

Loops of razor wire were stretched across the road on the northern, Serb side of the Ibar river dividing Mitrovica. They also surrounded the courthouse at the centre of Monday's clashes in which a Ukrainian UN policeman died from suspected grenade wounds.

Condoleezza Rice, the US Secretary of State, led calls for restraint after 150 were wounded in the worst day of violence since the fledgeling state declared independence a month ago. But alongside her in Moscow, Sergei Lavrov, Russia's Foreign Minister, underlined the wide divide among world powers when he restated opposition to Kosovo's split from Serbia.

In a café facing the barricaded river crossing Serbian campaigners were in no mood to back down. This is the spot where the divide between Kosovo's main ethnic communities is in danger of becoming the partition line of the new country into the mainly Albanian south and the Serb north.

“If they want independence, well OK - but not on Serb territory,” said Nikola Kabasic, who was a judge working at Mitrovica court until the UN took control in 1999 after the expulsion of Slobodan Milosevic's Serb forces.

“We shall continue our protest until that building is a court which belongs to the people who live here and who have a right to have a judiciary from their own community,” he said.

The showdown over the court is seen as the latest step in a Serb campaign to assert authority in the north, after attempts to seize key rail lines and attacks on border posts after the independence declaration on February 17.

The UN has withdrawn its police and judicial staff from northern Mitrovica, leaving a state of martial law, with French and Spanish Nato soldiers patrolling the streets and guarding the empty court building.

A UN spokesman defended Monday's dawn raid on Serb protesters who had occupied the court, saying that it had learnt that a second UN building was about to be occupied. The spokesman added: “We spent three days trying to get the protesters out in a peaceful manner. The credible information that there was a plan to take over another building left no alternative but to retake the courthouse.”

The UN police are expected to come back as soon as relative calm returns but the violent flare-up showed the tinderbox atmosphere facing the EU when it takes over the UN's responsibility for police and judicial issues in Kosovo later this year.

A pathfinding EU mission has abandoned its headquarters in northern Mitrovica after bomb threats and there is widespread hostility from the Serbian population after 16 EU nations formally recognised Kosovan independence.

“Serbs will definitely not accept the EU, there will be a whole new load of trouble,” said a 28-year-old man near Mitrovica's main bridge.

“It would mean that the Kosovan government will control the north part of Kosovo where Serbs are living. The best thing is for Kosovo to stay part of Serbia but obviously the EU and the Americans do not like this.”

Mr Kabasic added: “We already have effective partition in Kosovo. We have nationality partition, we have political partition and we have religious partition. You have two separate worlds.”

The warning that Kosovo was heading for long-term, unresolved conflict came from the International Crisis Group in a report on the first month of independence. It recommended that the Government in Pristina, the EU and Nato press more countries to recognise Kosovan independence. Only 28 countries have given formal approval so far. It also called for an urgent strategy for dealing with interference from Serbia.

The group gave warning: “Belgrade is pushing Kosovo Serbs to break all contacts with Kosovo institutions and is strengthening its own control in the north. It has instructed Kosovo Serbs to oppose the new EU missions.

“There is a real risk that partition will harden at the Ibar river in the north, and Kosovo will become another frozen conflict, like the breakaway regions of Abkhazia or Nagorno-Karabakh,” it said.

Besim Hoti, a spokesman for the Kosovo police service based on the south side of the Ibar river, saw grounds for optimism despite the outbreak of violence. “We have still not had any direct clashes between the ethnic communities which is very encouraging and important for future security,” he said.

City on the edge

— Mitrovica, about 50 miles northwest of the Kosovan capital, Pristina, was the focal point of the March 2004 riots that erupted across the region after rumours circulated that Serbs had been responsible for drowning an Albanian child

— Nineteen people - 8 Kosovan Serbs and 11 Kosovan Albanians - were killed, and more than 1,000 people wounded, including 120 police officers and international peacekeepers

— A steel truss bridge over the Ibar river divides the roughly 40,000 Serbs living in the north from the 80,000 Kosovo Albanians in the south

— In late 2003 there was a slight lessening of tension between north and south. The security measures on the main bridge were relaxed and provided by Kosovo police rather than Nato

— About 77 per cent of the population are unemployed

Sources: Organisation for Security and Co-operation in Europe; Encyclopaedia Britannica

Times Recommends

• 'Radio Rancid' is scourge of Obama
• French gulp as global warming alters wines
• Colton, the barefoot boy bandit, outfoxes sheriffs