UN Secretary-General Kofi Annan opened the meeting with an appeal for resources to get the UN civilian administration functioning and to speed up the deployment of Nato-led peacekeeping troops to establish security in Kosovo.

But Mr Annan's call for an accelerated security presence came as more evidence emerged of atrocities against Kosovo Albanians. Peacekeeping troops near the town of Pec discovered the charred remains of 11 people - all thought to be members of the same family.

There were also signs that the Yugoslav Army was putting pressure on the borders of Montenegro, the junior partner in the Yugoslav Federation, with reports of barbed wire obstacles positioned at a checkpoint at the Bay of Kotor.

Obstacles known as "stingers" replaced tanks reportedly deployed by the army on Tuesday. Roadblocks had been in place for weeks at the motorway checkpoint, but they were removed on 27 June after the state of war was lifted.

The independent Montenegrin news agency Montena-fax also reported that Yugoslav troops had set up checkpoints on roads leading from Montenegro to Albania, Croatia and the Bosnian Serb Republic. Humanitarian aid was not being allowed through, the agency said.

'Building the peace'

High-level officials, including foreign ministers, from 16 nations and three international organisations are meeting in an attempt to boost the twin operations of the UN and Nato to return hundreds of thousands of refugees to Kosovo.

The BBC's Michael Voss reports: Keeping the peace between Serbs and Albanians is K-For's biggest headache

Arriving for the meeting, UK Foreign Secretary Robin Cook said: "What we must do today is make sure having won the war, we are now in a position to build the peace, working with the local population and working with the international community.

Mr Cook said General Sir Mike Jackson, commander of K-For, the Nato-led peacekeeping force, reported that 24,000 troops of the expected 50,000-strong force were now on the ground.

The UK foreign secretary said although the deployment had been carried out with "remarkable professionalism and competence", there are "very serious problems", many related to the absence of a UN civilian police force and a functioning law and order system.

The flood of returning refugees is a big challenge for the UN

To date the UN is reported to have pledges for about 1,300 civilian police, including a new US commitment to send 450.

But the UN is actually looking for a 3,000-strong force, and also needs administrators to run municipalities and other government operations, a UN official said on Tuesday.

Foremost among the immediate challenges facing the UN operation was the flood of refugees returning to the province and internally displaced people, which "exceeds any on record", Mr Annan said.

The UN secretary-general said the humanitarian needs of all citizens of Yugoslavia must be served. This included "restoring electricity and water supplies". These installations were destroyed during Nato's 11-week bombing campaign.

Atrocities

The BBC's Michael Voss reports: Mrs Robinson called on the international community to have a greater presence on the ground

In the province itself, Italian troops have discovered the charred remains of 11 people in a burnt-out house in the village of Kalilane, near Pec. The BBC's Michael Voss, who is in the province, says this region of western Kosovo suffered some of the worst ethnic cleansing and atrocities allegedly committed by Serb forces.

With the return of the refugees, the remaining Serb and gypsy communities have suffered from repeated revenge attacks. This time the victims are believed to be Kosovo Albanians, although the motive for these latest killings is unknown, our correspondent says.

(Click here to see a map showing refugee movements)

The UN's High Commissioner for Human Rights, Mary Robinson, has demanded that Yugoslav President Slobodan Milosevic be called to account for alleged atrocities committed in Kosovo after seeing for herself evidence of mass killings near the provincial capital Pristina.

Mary Robinson called for President Milosevic to stand trial

She said: "We must break the cycle of impunity. We know that President Milosevic and four other senior figures have been indicted. It is my hope that they will stand trial."

Mrs Robinson also visited a refugee camp in Pristina where several thousand gypsies have fled to escape violence by Kosovo Albanians who accuse them of having looted their homes after they were forced to flee by Serb forces.

"It's very distressing," she said. "Most of these people have come to this camp very recently. They have been forced to leave their homes.

"Babies have been born here, old people are obviously suffering greatly and they're in fear because they don't know where to go."

• Analysis: Milosevic and the opposition threat
• Rebuilding the Balkans
• Refugees 'given unusable drugs'
• Montenegro edges towards independence
• Analysis: The UN's task in Kosovo