NATO peacekeepers moved on Thursday to close off illegal routes across Kosovo's northern border with Serbia, stepping up pressure on Serbs in the region who have blockaded the official crossing points.
Serbs in the north of the majority-Albanian country are blocking the two main roads running south from the border in protest against a move to establish Kosovo customs and police on the frontier. Alternative routes have opened up, bypassing customs checks.
Serbs in the north reject Kosovo's 2008 declaration of independence from Serbia, and violently resisted an attempt in July by Kosovo's ethnic Albanian authorities to take control of the two main border crossings.
NATO helicopters helped establish a skeleton customs and police presence at the two gates last month but the roads remain blocked in a challenge to the West's efforts to reverse Kosovo's de facto ethnic partition.
NATO's 6,250-strong Kosovo Force, KFOR, said it had launched an operation "to establish control" in the vicinity of the Jarinje crossing, "to help prevent the illegal use of the bypass around the official gate and to stop smuggling."
It said in a statement that it was acting at the request of the European Union police and justice mission established in Kosovo after the 2008 declaration of independence.
KFOR commander Major-General Erhard Drews said: "KFOR reserves the right to remove the barricades when appropriate and will not tolerate them endlessly."
The operation took place a day after the European Commission recommended Serbia be granted official candidate status for membership of the European Union, but said the start of accession talks would depend on Belgrade improving relations with its former southern province.
Serbia lost control over Kosovo in 1999 when NATO bombed for 78 days to halt the killing and expulsion of ethnic Albanian civilians in a two-year counter-insurgency war.