With refugees fleeing across the border into northern Albania, the Albanian Prime Minister, Fatos Nano, accused the Serbian authorities in Kosovo of pursuing a deliberate policy to drive out the majority ethnic Albanian population.
He said the violence could lead to war if it was not halted.
Click here to see an interactive map of the main flashpoints in the region.
The Albanian government says 2,000 refugees have arrived since the start of the weekend. The refugees are believed to have come from border villages where there has been fighting between Serbian troops and the underground Kosovo Liberation Army (KLA).
A spokesman for the United Nations Refugee agency, Tam Meechu Bot, said several thousand more ethnic Albanians were reported to be on the move.
Difficult to return
The Albanian interior ministry says it is by far the biggest wave of refugees since Serbian security forces in Kosovo began a major offensive against armed ethnic Albanian separatists at the end of February.
![[ image: width=150]](/olmedia/100000/images/_104069_kosovomapUSE.jpg)
A spokesman, Artan Bizhga, said the refugees were mainly women, children and the elderly, many of whom had walked for as many as 10 hours. They were being accommodated in local homes and a school, and local authorities were providing free food and clothes.
BBC correspondents say that most ethnic Albanians are afraid to flee because of the difficulty in returning to their homes once they have left.
The border between Yugoslavia and Albania has officially remained closed since last year's uprising against the former Albanian President, Sali Berisha. It is also tightly guarded by the Yugoslav army in an attempt to keep out KLA reinforcements.
Nato dilemma
Last week, Nato announced a series of measures to heighten its military presence on the borders between Kosovo and Albania and Macedonia, with a veiled and indirect threat of military intervention in Kosovo itself.
As the fighting continued, a Nato spokesman, Nicolas Fiorenza, said that no action had been ruled out.
But the BBC Defence Correspondent says that Nato is unlikely to intervene because Kosovo is officially part of another country - Serbia - and therefore the legal basis for an intervention would be questionable.
Our correspondent says that if Nato chooses to contain the situation from the border, it could risk blocking the escape routes of ethnic Albanians, and thus inadvertently supporting the Serb forces.
The Yugoslav President, Slobodan Milosevic, has refused to accept international mediation in a dialogue over Albania, although there have been talks between the Serbian authorities and ethnic Albanian politicians.
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