BELGRADE, Dec 28 — Kosovo closed its biggest border crossing with Serbia, police said today, after Serbs set up more barricades on their side in one of the worst regional crises in years.

Kosovo declared independence from Serbia in 2008, but Belgrade has refused to recognise it and encouraged Kosovo's 120,000 ethnic Serbs to defy Pristina's authority — especially in the north where ethnic Serbs make up the majority.

The latest trouble erupted on December 10, when ethnic Serbs put up barricades to protest the arrest of an ex-policeman suspected of being involved in attacks against ethnic Albanian police officers —effectively sealing off traffic on two border crossings.

After the roadblocks were erected, Kosovar police and international peacekeepers were attacked in several shooting incidents, while the Serbian armed forces were put on heightened alert this week.

Late yesterday, dozens of demonstrators on the Serbian side of the border used trucks and tractors to halt traffic leading to Merdare, the biggest crossing between the neighbours — a move which forced Kosovo police to close the entry point on Wednesday.

"Such an illegal blockade has prevented the free movement and circulation of people and goods, therefore we invite our citizens and compatriots to use other border points for circulation," Kosovo police said in a statement.

Pristina also asked Nato-led peacekeepers to clear the barricades that were erected on Kosovo soil.

Serbian Defence Minister Milos Vucevic today said Belgrade was "ready for a deal", but did not specify other details.

Vucevic described the roadblocks as a "democratic and peaceful" means of protest and added that Belgrade has "an open line of communication" with Western diplomats on resolving the issue.

"We are all worried about the situation and where all this is going... Serbia is ready for a deal," Vucevic told state-controlled public broadcaster RTS.

Northern Kosovo has been on edge since November when hundreds of ethnic Serb workers in the Kosovo police as well as the judicial branch, including judges and prosecutors, walked off the job.

They were protesting a controversial decision to ban Serbs living in Kosovo from using Belgrade-issued vehicle licence plates —a policy that was eventually scrapped by Pristina.

The mass walkouts created a security vacuum in Kosovo, which Pristina tried to fill by deploying ethnic Albanian police officers in the region.

The EU and several international ambassadors this week condemned four recent attacks against journalists who were covering the flare-up. —AFP