As reports came in of fresh atrocities, President Clinton left Washington for Europe to pursue diplomatic resolutions to the crisis, and pay visits to Nato HQ in Brussels and US forces in Germany.

Increasing numbers of abused refugees are arriving in Albania and Macedonia, their condition is worse, and the stories of men being taken away and murdered more insistent.

Reporting from Kukes in Albania, the BBC's correspondent Fergal Keane says thousands crossed into Albania on Tuesday and more are on their way.

Nato says those fleeing to the province's borders have been "ethnically cleansed" from their homes.

Our correspondent says it is difficult to believe the kind of terror people at the camp describe.

Duncan Kennedy: "Mr Clinton intends to get a first-hand account of how the campaign is going"

The evidence of physical violence is increasingly a cause for concern.

Many refugees report being stopped by Serb police and menaced for money. Those who refuse to pay are shot.

One man shot by Serb police watched two companions die

One man in the camp said he was shot by Serb police who demanded money from him.

He was lucky. Two others in his convoy were shot dead.

"I saw them take a young man and throw him in the river. They shot him three times," he said.

Moving away from danger

On Tuesday, the UN refugee agency running Albanian camps told the BBC it believes that refugees could be in danger from Serb artillery even outside Kosovo's borders.

The UNHCR's Ray Wilkinson: "Well within artillery range"

According to a UNHCR spokesman, the agency is seriously considering closing six large camps and moving people south.

But at the same time, the Albanians may also have to cope with a further influx of Kosovo refugees who have overwhelmed the authorities in Macedonia.

Aid agencies in Macedonia trying to cope with a new influx of Kosovo refugees say they are having to take new measures to deal with security and overcrowding problems.

Fergal Keane in Albania: One of the most terrible days yet

Meanwhile, the UK has agreed to give sanctuary to 1,000 Kosovo Albanian refugees a week.

The Home Secretary, Jack Straw, said that within a few weeks a plane-load of displaced Kosovo Albanians could be arriving in the UK every day.

Second Apache crash

A Western military spokesman in Albania says an American Apache helicopter has crashed during a training mission north-east of the capital, Tirana.

One of the crewmen has been killed in the incident, and the other is missing.

It is the second Apache to crash in the past 10 days.

Meanwhile, Yugoslavian media says a Nato plane was shot down near the Bosnian border as improving weather allowed intensified attacks.

A Nato spokesman said he had no information on this.

Yugoslav media say Nato aircraft have carried out new attacks in central Serbia, with explosions at Novi Pazar, Kadinjaca and Bajina Basta.

Electric power has been reported cut off Belgrade.

(Click here to see a map of last night's Nato strikes)

Clinton standing firm

President Clinton has left Washington for Europe to visit Nato HQ in Brussels, and US forces in Germany.

Before leaving the president said he will explore every diplomatic avenue to resolve the crisis, but that Yugoslavia had to meet Nato's demands.

President Clinton: "Willingness to seize every diplomatic possibility"

"We have to take a stand. We have done that. We have to see our effort through. We will do that," he said.

Reports from Washington say Mr Clinton may release two Yugoslav soldiers held by Nato - after the release this week of three US soldiers from Belgrade.

However, the BBC's Washington correspondent says this would be a one-off gesture and not a sign of a change in overall policy.

Russian efforts continue

Russia's special Balkans envoy, Viktor Chernomyrdin, has continued his efforts to find a diplomatic solution to the conflict during a visit to the US.

He held talks with the United Nations Secretary-General Kofi Annan in New York.

Following their meeting, Mr Chernomyrdin said that there would be a Russian element to any international presence in Kosovo, but confirmed that it still has not been decided whether it should be a military presence or not.

The UN Secretary General intends to appoint two special envoys of his own who will work closely with Russia in their attempts to search for a solution.

Mr Annan has asked Yugoslavia for permission to send a UN humanitarian team into Kosovo to assess the situation on the ground.

Mr Annan says he is not asking for a pause in Nato's bombing campaign to enable his team to visit.

He wants to examine the conditions into which refugees might have to return in the future.

Politicians criticised

A leading Nato commander has criticised the campaign against Yugoslavia, saying political considerations are making the conflict longer.

General Klaus Naumann, the outgoing chairman of Nato's military committee, said the need to maintain unity among the 19 members meant Nato had been unable to use surprise or sufficient force.

"This cost time, effort and potentially additional casualties and the net result being that the campaign is undoubtedly prolonged," he said.

The criticism came as Nato denied that it had bombed a bus carrying civilians in Kosovo on Monday.

Serbian sources said 20 people had died and 43 had been injured in the incident.

The alliance said although several Nato aircraft had been in the general area, film of the bus indicated that it had not been attacked from the air.

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