Serbian troops were also reported to have shelled a line of refugees, killing one and injuring 22 at the same border crossing at Morina.

The refugees' car exploded just 20 metres from the border, said the Organisation for Security and Co-operation in Europe (OSCE).

It was part of a convoy that had brought about 1,500 refugees across the border in the early hours of Sunday.

A BBC correspondent in Albania, Duncan Kennedy, says Serbian troops had been seen laying mines there a few days ago, apparently to fortify the areas in the event of a Nato ground attack.

Duncan Kennedy reports: "A renewed push by the Serbs"

He says the car appears to have strayed from the safe route through the minefield.

More than 23,000 Kosovo Albanians passed through the same point at Morina on Saturday in cars, tractors and on foot.

Tens of thousands of refugees are reportedly at border check-points intending to cross, with aid agencies in northern Albania reporting the first cases of malnutrition among children crossing from Kosovo.

Relief workers say some refugees have told them they had to bury children along the road who were simply too weak to make the journey. Others bear injuries they blame on Serb security forces.