The World Food Programme says that hundreds of thousands of people have been seen heading towards Albania, Montenegro and Macedonia.

The UNHCR reports that a convoy of refugee vehicles more than 20 km long is heading south from the Kosovo capital, Pristina.

The internal movement comes amid fears that the Yugoslav authorities are forcibly preventing people from leaving the province.

Orla Guerin reports on the implications of war in the Balkans for Italy

Over the weekend, Kosovo Albanians were reportedly pouring out of Kosovo at the rate of over 1,000 an hour.

But the outpouring has now been reduced to a trickle, and the Albanian border has been closed since Belgrade severed diplomatic relations.

(Click here for a map showing refugee movements)

A UNHC spokesman in Geneva said refugees were having to pay heavy bribes to Serb soldiers and border guards to get across.

Our correspondent in Albania, Jeremy Bowen, described the sudden stop in refugees crossing the border as "eerie and rather spooky".

Refugees on the Macedonian border near Blace say packed trains and buses were being turned back.

Hiding in mountains

The aid agencies say they have ordered an extra six million emergency food rations to cope with the expected refugee influx.

The World Food Programme says around 175,000 of the internally-displaced people inside Kosovo are travelling towards Montenegro, and 100,000 people are heading for Macedonia.

A spokeswoman in Albania said it was unclear where the rest were going, but they were probably trying to flee Serb tanks.

"They are heading towards the mountains, I think, to escape the tanks. I'm sure that some of those people will eventually wind up here in Albania," said Angela Walker.

Children suffer from malnutrition

Relief officials in northern Albania said the latest arrivals were in the worst condition they had seen, with children suffering from malnutrition.

Some refugees have told relief workers 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.

The refugee agencies are also reporting a diarrhoea epidemic.

A spokeswoman for the UN children's agency says fewer than half of the Kosovo Albanians have been vaccinated, due to a widespread mistrust of the Yugoslav-run health authorities.