In a visit aiming to boost support, stiffen Nato resolve and quell any doubts that the US was wavering, he said those involved in the Kosovo campaign were helping to make the world safer for the 21st Century.

Mr Clinton condemned racial and ethnic intolerance, and stressed that Nato would continue and intensify its air campaign against Yugoslavia, unless President Milosevic withdrew his forces from Kosovo.

David Shukman in Germany: The President met the men he has ordered to bomb Serbia

"We are hitting them hard where it hurts - on the ground in Kosovo," he told soldiers on a visit to Spangdahlem military base, shortly before meeting the three US soldiers released by Yugoslavia on Sunday.

"We have no quarrel with the Serb people," said the US president.

President Clinton: "Willingness to seize every diplomatic possibility"

"Our quarrel is with ethnic cleansing."

President Clinton goes on for talks with Chancellor Gerhard Schröder - a meeting intended to boost the German leader's position, as his government faces growing public opposition to the war.

Yugoslavia allows moderate abroad

Ibrahim Rugova (left) with the Italian prime minister

In an unexpected development, Kosovo Albanian leader Ibrahim Rugova and his family arrived in Rome on Wednesday, with the approval of Belgrade.

He was flown in by an Italian military plane and went straight into talks with the Italian prime minister, Massimo D'Alema.

The moderate leader has been calling for an end to Nato military action and a peaceful solution to the Kosovo crisis, but western governments say he has been under the control of the Yugoslav Government.

Nato and the US State Department welcomed the development.

Yugoslav media say Nato aircraft have carried out attacks in central Serbia, with explosions at Novi Pazar, Kadinjaca and Bajina Basta. Electricity supplies were cut off in Belgrade.

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

Nato is to base 24 F-18 fighter bombers in southern Hungary, according to the country's Defence Minister, Janos Szabo.

It will be the first time Nato attack aircraft for the Kosovo conflict will have been based in the only Nato member state bordering Yugoslavia.

Mark Laity in Brussels: There is a greater sense of optimism that the campaign is working

Earlier Mr Clinton met Nato leaders in Brussels.

The alliance's Supreme Allied Commander in Europe, General Wesley Clark, told the president that Nato was winning, and that the Yugoslav leadership and its military and security forces were vulnerable to collapse.

However he acknowledged it may be next spring before ethnic Albanians forced out of Kosovo can go home to anything like a normal life.

He also said the allies were working on enhancing the Kosovo "enabling force" in Macedonia, which was originally envisaged as a 28,000 strong peacekeeping force.

Meanwhile, Yugoslavia has again said it will accept only an unarmed peacekeeping mission for Kosovo.

A Foreign Ministry spokesman said Yugoslavia did not need an occupying force for the province.

His comments follow speculation that President Slobodan Milosevic could be moving towards accepting a lightly armed peacekeeping force.

Earlier, US Defence Secretary William Cohen said he would shortly recommend the release of two Yugoslav prisoners of war held by allied forces.

The announcement came three days after Yugoslavia released three US prisoners of war in response to an appeal by the Reverend Jesse Jackson.

More accounts of abuse

The government of the Former Yugoslav Republic of Macedonia has again shut its Blace border crossing, stopping hundreds of Kosovo refugess from entering the country, say UN officials.

Refugees continue to bring tales of atrocities

Increasing numbers of refugees are arriving in Albania and Macedonia, bringing more and more stories of men being taken away and murdered.

After an emergency meeting on Wednesday, Macedonia won a pledge of more than $250m from international donors.

Duncan Kennedy: Clinton's job is part political, part military

The new aid was announced by Macedonia's Finance Minister Boris Stojmenov and World Bank and European officials after a meeting in Paris intended to provide a rapid response to the danger to Macedonia's fragile economy due to the war in Yugoslavia.

On Thursday in Germany the ministers from the G7 industrialised nations and Russia are set to discuss common principles for demanding Belgrade pull its troops out of Kosovo and allow the return of refugees.

• Two die in Apache crash
• No limits on UK refugees
• US Senate shelves Kosovo motion
• Politics 'hurt' Nato strikes
• Germany faces Kosovo criticism