MITROVICA, Serbia and Montenegro (Reuters) - A U.N. plan to let traffic cross the bridge in Kosovo's ethnically divided town of Mitrovica for the first time since the war fell at the first hurdle on Monday, as Serbs blocked the north side.
U.N. police in the disputed province want to open the bridge to civilian cars for two hours a day, gradually increasing access until cars can cross non-stop by mid-July.
But in an early setback, some 300 Serbs who had been gathering since the early morning calmly blocked the path of the first car to approach the bridge from the southern Albanian-dominated side.
Police turned the car back and the crowd later dispersed.
"Our wounds are too fresh," said one elderly Serb man. "This is too early."
Serbs see the north as their last urban stronghold in the 90-percent Albanian province, now run by the United Nations.
Nearly 200,000 fled in 1999 in fear of Albanian revenge attacks after 78 days of NATO bombing drove Serb forces out, ending a two-year Albanian insurgency.
There has been sporadic ethnic violence ever since and Mitrovica has seen some of the worst of it.
Serbs fear if security is relaxed they may face attacks by Albanians wanting to take back apartments they fled in the war.
"People will keep gathering ... because it's a threat to their survival," said local Serb politician Marko Jaksic.
But the United Nations said the operation would go on as planned, and the bridge would be opened for a second hour in the afternoon.
"The decision is to proceed as planned. We understand their concerns but we have to support the principle of freedom of movement," spokesman Gyorgy Kakuk told Reuters.
The standoff came just hours before the arrival of U.N. envoy Kai Eide, who will assess Kosovo's readiness for negotiations on its "final status" -- whether it becomes independent or remains nominally part of Serbia.
For Kosovo Albanians, who want independence, hardline Serbs in the north represent the front line for a possible attempt by Serb leaders in Belgrade to partition the province.
The River Ibar provided a convenient natural barrier between the town's Serbs and Albanians with French NATO troops patrolling the heavily fortified bridge and allowing only pedestrians to cross in small numbers.
Albanians and Serbs traded automatic gunfire over the river in March last year, sparking two days of Albanian riots across the province in which 19 people died and 4,000 fled their homes.
The situation has been relatively calm since and French troops have gradually relaxed security on the bridge, handing control last week to the multi-ethnic Kosovo Police Service.
The West hopes to open negotiations aimed at settling Kosovo's fate in September, provided Eide says the province has made sufficient progress toward benchmarks of security, law and order and minority rights.