The crunch has come after four months of blowing hot and cold in the international community over how to make Yugoslav President Slobodan Milosevic comply with United Nations demands.

Belgrade's critics say the campaign by federal Yugoslav and Serbian forces against separatists in Kosovo has caused unwarranted hardship to the majority ethnic Albanian civilian population, destroying their homes and sending thousands fleeing into the countryside.

A western diplomat explained the problems in finding a common stance. He said that the question of the right to interfere in a country for humanitarian ends was very difficult to handle.

NATO's decision will be made in the light of a report due on Monday from UN Secretary General Kofi Annan to the Security Council on whether there are grounds for airstrikes against Serbia.

Thisreport would constitute an appropriate legal basis for action, according to diplomats, but they do not rule out yet another Security Council resolution with the backing of Russia.

Moscow, which is sympathetic to Belgrade, has so far held the view that military action will not help to reach a political solution to the Kosovo problem.

NATO's position is that airstrikes would be part of a combined political and military strategy aimed at ending the violence in Kosovo, avoiding a humanitarian tragedy with the onset of winter, and obliging the opposing sides to negotiate. At NATO headquarters, opinions are divided on whether airstrikes will take place. Some diplomats say the United States is determined to teach Milosevic a lesson, and Washington's allies in London, Paris and Bonn have few scruples about following suit. Others say the Yugoslav President has begun to make concessions. On Friday, Belgrade said it was withdrawing its military and police formations to their barracks in the province. It also claimedits operations had ended despite reliable reports of continuing clashes.

It was reported that the head of the Serbian negotiating team with Kosovo's Albanian political leadership, Ratko Markovic, had invited the Albanians to new talks on the future of Kosovo.

The chief Albanian negotiator Fehmi Agani rejected the offer saying that conditions for holding a dialogue were not yet right.

On Saturday, Zoran Anbjelkovic, the official appointed to head a provisional government for Kosovo, said an 18-member council made up of representatives from the region's Albanian, Serb, Turkish and Muslim communities had been formed.