"There is always a cost to defeat an evil. It never comes free, unfortunately. But the cost of failure to defeat a great evil is far higher," said Nato spokesman Jamie Shea.

He insisted Nato planes had bombed only "legitimate designated military targets" and if more civilians had died it was because Nato had been forced into military action.

BBC's David Sillito: The number of civilian injuries continues to grow

Yugoslavia says at least 20 people were killed when Nato planes hit a sanatorium and a neighbouring old people's home during a midnight raid in the town of Surdilica in south-eastern Serbia on Sunday.

Another 11 are reported to have died in an attack on a bridge in Varvarin, south-central Serbia, and one person died when a bomb hit a car carrying foreign journalists.

Wreckage of the bridge at Varvarin

Alliance military spokesman General Konrad Freitag said Nato warplanes had successfully hit an ammunition storage depot and a military barracks in the raid on Surdulica.

Nato is still investigating the claims of civilian deaths.

Nato also described the attack on the bridge at Varvarin as a "designated and legitimate target".

Mr Shea said: "Nato does not attack civilian targets, we attack exclusively military targets and take every precaution to avoid inflicting harm on civilians."

According to Belgrade, at least 11 civilians were killed and 40 injured.

Jon Leyne reports: "NATO denies allegations that its bombs are going astray"

Yugoslav news agency Tanjug said the area would have been crowded with people attending the town market at 1pm local time (1100GMT) on Sunday, the time of the attack.

Witnesses said four cars fell into the River Velika Morava during the first waves of attacks and rescuers who went to help victims were hit in a second wave of bombings.

(Click here to see a map of latest Nato strikes)

Tanjug also reported a car carrying foreign journalists in Kosovo was hit on Sunday, although Nato says there is no evidence an alliance plane was involved.

Jamie Shea: We have no information so far that we were responsible

The driver of the car, who was an interpreter, was killed and one British, one French and one Italian journalist had been injured, said the agency.

Eve-Ann Prentice of The Times newspaper was treated in a hospital in Prizren but has since been released.

Milosevic peace move

Yugoslav President Slobodan Milosevic has confirmed he will accept the G8 principles for ending the Kosovo conflict.

In a statement issued to Serbian radio, he said: "In line with our consistent policy of peace and defence of freedom, the Federal Republic of Yugoslavia has accepted the G8 principles and believes that the UN Security Council, in line with the UN Charter, should now make it possible with its resolution to move the solution to the crisis from the military to the political track."

The US reacted with caution, saying it welcomed any positive development but it was not clear all the terms had been accepted.

Michael Williams, a BBC correspondent in Belgrade, said Yugoslavia first accepted the G8 principles as a basis for negotiation some three weeks ago.

But he said it was perhaps significant that the announcement had finally come from the highest echelons of government.

Clinton calls for support

US President Bill Clinton has urged Americans to support the Kosovo campaign.

"What we are doing today will save lives, including American lives, in the future and it will give our children a better, safer world to live in," he said in his Memorial Day address.

Mr Clinton said that if the United States was more heavily involved than other countries, it was because the US had a greater capacity.

Jeremy Cooke reports: "The fighting threatens to spread into Albania itself"

In another development, there has been upsurge in fighting between Serb forces and the Kosovo Liberation Army along the border between Kosovo and Albania.

Serb shells hit an area less than a mile from the Morino crossing point used by hundreds of refugees every day.

Aid agencies in the nearby town of Kukes have warned that the area is becoming increasingly unsafe.

Some 2,000 refugees a day are being taken to camps further south, although many are unwilling to move away from the border, and from home in Kosovo.

• Picture gallery: Nato destruction
• 'No plans' for Kosovo call-up
• Conspiracy theories take shape
• Nato promised 'hell' in Kosovo
• Times reporter leaves hospital

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