British and American officials are reported to be working on a resolution for submission to the United Nations.

The British Ambassador to the UN, Sir John Weston, said the UN Security Council would be "actively seized of the subject in the next few days."

He added that the Yugoslav President Slobodan Milosevic could not be allowed to seek a military solution to the situation.

The US Ambassador to the UN, Bill Richardson, told journalists: "We are about to work closely with the British and our European allies in bringing this issue to the Security Council."

The options under discussion include further economic sanctions against Yugoslavia and the deployment of Nato troops to prevent the crisis spilling into neighbouring countries.

However, correspondents say that any resolution authorising the use of force against Yugoslavia is likely to be opposed by Russia.

The United Nations Secretary-General, Kofi Annan, has said he is deeply disturbed by what he called atrocities committed by Serb military and paramilitary forces against unarmed civilians in the Serb province.

The Security Council has called for humanitarian organisations to be given immediate and unimpeded access to all parts of Kosovo.

Nato defence ministers and the international Contact Group are set to meet next week to decide what action to take.

Thousands seek refuge across the border

More than 200 people are reported to have been killed in Kosovo over the past three months in an offensive by Yugoslav security forces against the Kosovo Liberation Army.

At least 17,000 people have fled to Albania and Montenegro to escape the fighting, and many who have fled their villages are believed to have taken refuge in the mountains inside Kosovo.