Meeting in London, the international Contact Group said the province of Kosovo must be granted "substantial autonomy" from Serbia.

The Contact Group chairman, UK Foreign Secretary Robin Cook, summoned both sides in the Kosovo conflict to meet for talks within a week. The Serbs and Albanians have been given a total of three weeks from Friday to finalise a peace deal.

BBC Special correspondent Ben Brown: "Today, it was business as usual" (WARNING: Some users may be upset by some scenes)

But as diplomacy reigned in London, violence continued to flare in Kosovo, with reports of fresh fighting.

International monitors in Kosovo say 25 men have been found shot dead in the western village of Rogovo.

They included a Serb policeman and three fighters of the rebel Kosovo Liberation Army.

'Bomb to avenge KLA deaths'

Later a bomb exploded near a cafe frequented by Serbs in the capital, Pristina injuring seven people. The police said they found a message at the scene saying the bomb was to avenge KLA deaths.

OSCE spokesman Sandy Blyth: "This is another incident of a shocking nature"

OSCE spokesman Sandy Blyth refused to call the Rogovo incident a massacre and said: "There was a shooting at around dawn when one police officer was killed.

"In the subsequent police operation 24 Albanians were killed. Three were in KLA uniform and the rest were in civilian clothes."

'Get serious'

After three months in which there had been no talks between the two sides to negotiate a political outcome, the international community appears to have lost patience.

Robin Cook: "Those who want war have got to be marginalised"

Mr Cook said the Contact Group could not allow a stalemate to continue "while the ceasefire crumbles and people are being killed".

His strong words were echoed by US Secretary of State Madeleine Albright. "We have sent the parties an unmistakable message - 'Get serious'. Showing up is not going to be good enough", she said.

Threat of force

A statement after the London talks said both the Yugoslav authorities and ethnic Albanian leaders would be held accountable if the negotiations failed. Correspondents say the wording clearly carries the threat of Nato military action.

Earlier Nato warned the proposals would be imposed by force if negotiations were not opened within a few days.

Britain, France and Germany have underpinned Nato's warning by saying they were prepared to send ground troops to Kosovo to enforce a negotiated settlement.

Robin Cook: "A very tight timetable"

But it remains unclear whether the US would support such a move. Ms Albright said the Clinton administration would consult Congress about a possible role for US troops in enforcing an interim peace deal.

Later on Friday, President Clinton said the US and its allies were united behind the international political process, and were "ready to back that strategy with the threat of force".

Proposals for peace

The Contact Group paper proposes "a self-governing Kosovo with free and fair elections supervised by the OSCE and with control over their own police and internal security", said Mr Cook.

Mr Cook is to fly to Yugoslavia to reinforce the Contact Group's demand to the Belgrade authorities and ethnic Albanian leaders in Pristina to sit down to peace talks.

Mixed response

The Contact Group's proposals have received a mixed welcome from the two sides themselves.

Yugoslav President Slobodan Milosevic indirectly rejected an international conference on Kosovo, calling instead for direct talks between all ethnic communities in the province.

A statement - which made no mention of the Contact Group meeting - said problems in Kosovo should be solved peacefully "through direct political dialogue between the representatives of national communities that live in Kosovo and Metohija and state bodies."

Earlier Serbian Deputy Information Minister Miodrag Popovic welcomed the talks, but said Serbia's forces could not observe a ceasefire - a precondition set by ethnic Albanian leaders.

BBC Diplomatic correspondent James Robbins: "This was the day the key powers finally lost patience with both sides"

"We can't speak of any ceasefire because we consider the KLA a terrorist organisation."

Moderate Kosovo Albanian leader Ibrahim Rugova said he would send representatives to the peace talks in France, but was not yet sure if he himself would go.

Barnaby Mason considers the chance of success

But he warned: "We cannot move ahead with negotiations ... that would eventually serve as a cover-up for the massacres and the killings that Belgrade has been committing."

Racak killings

Ahead of the London meeting, a report in The Washington Post newspaper alleged that the 40 ethnic Albanians found dead in the village of Racak were killed by regular security forces acting on the orders of Belgrade.

Yugoslav authorities have maintained that the victims were ethnic Albanian guerillas who died in combat with Serb forces, and that the bodies were moved by the KLA and made to look like the victims of a civilian massacre.