NATO says it is closing the border crossings for 24 hours to allow tensions to ease.
On February 19, hundreds of Serbian protesters set fire to the customs and police posts at Jarinje and Brnjak on the Serbia-Kosovo border. The attackers forced the UN and Kosovar police manning the posts to retreat. Witnesses say the crowds then used explosives to destroy the facilities.
Soldiers from KFOR, the NATO-led peacekeeping force, have now secured the area. The troops, from the United States, Estonia, and France, have blocked the main road crossing with Serbia and sealed the crossing to Montenegro.
The border violence highlights the volatile situation in northern Kosovo, where ethnic-Serbian enclaves in the newly independent state adjoin Serbia.
Most ethnic Serb residents consider Kosovo's February 17 declaration of independence illegal, as does Belgrade. Militant groups in Serbia have regularly threatened action against Pristina's secession, but so far the violence has been sporadic and nonlethal.
The independence of Kosovo has been welcomed by key Western states, including the United States, Austria, Britain, France, Germany, and Italy, as well as Turkey, Afghanistan, and others.
But Russia, Spain, Romania, and Cyprus are among those states whose governments have vocally opposed the declaration. Those countries, with restive minorities of their own, say they do not want to see Kosovo become an international precedent for meeting secessionist demands.
Meanwhile, Belgrade is fighting a diplomatic rearguard action against its former province's secession.
Serbian Foreign Minister Vuk Jeremic is to press his country's claim to Kosovo when he addresses the European Parliament's Foreign Affairs Committee in Strasbourg on February 20.
But there are no signs the offensive will have any impact on the EU's commitment to supervise and financially aid the world's newest independent country.
"We will be here on the ground, with the citizens of the European Union in the mission of the European Union, economically helping you," EU foreign-policy chief Javier Solana said in Pristina on February 19. "European citizens will be in KFOR, therefore we'll be accompanying you in this process physically on the ground."
The head of the international civilian mission that will oversee Kosovo's independence, Pieter Feith, indicated on February 19 that he has begun work as the EU special representative there.
He said he is already deploying his office staff and that "the rule of law mission will start deployment during the coming weeks." The mission is a 2,000-strong police and judicial team to reinforce Kosovo's own fledgling administration.
The furor over Kosovo's independence declaration on February 17 still shows no sign of ending soon. Serbian political parties are organizing a mass "Kosovo is Serbia" rally for February 21.