Nato troops have sealed the northern borders of Kosovo after Serbs angry at its weekend declaration of independence ransacked two crossings.
Hundreds of protesters torched customs and police posts at Jarinje and Banja, manned by UN and Kosovo police.
Closing the borders will infuriate both Kosovo Serbs and Serbia's government, says the BBC's Nick Thorpe in Kosovo.
Since when has there been any historical precedent whatsoever for this as a solution to regional stability? The Serbs will never accept this and at the appropriate juncture will secede the northern part. This blog has said it and said it and said it - the NATO solution is no solution.