Speaking on US television, General Powell - who led United States forces during the Gulf War - said the exclusive use of air power had given Yugoslav President Slobodan Milosevic the decision as to when the Kosovo conflict would be ended.

Colin Powell is credited with developing the Powell doctrine during the Gulf War - the use of overwhelming force in a conflict to achieve defined objectives.

"Go all out ... war involves casualties," he said, echoing complaints by many military strategists that an air operation will never be enough to force President Milosevic to back down.

BBC's Mark Laity explains Nato's strategy since the latest civilian killings

The US Defence Secretary, William Cohen, responded by saying that Nato was going all out with its air campaign. Washington, however, remains determined not to send in ground troops to fight a war.

Exactly how and when troops might enter Kosovo will be discussed when UK Foreign Secretary, Robin Cook, visits the United States later this week.

Following another night of intense bombing in Yugoslavia, Nato chief Javier Solana said the bombing campaign was working and they would stick with it.

BBC News' Orla Guerin meets refugees in Macedonia

He told the BBC he wanted Kosovo Albanian refugees to return this year.

"It is our wish, and we are doing our best so they can return home as soon as possible, in any case before the winter."

'More determined than ever'

In a joint editorial in Sunday's Washington Post, the UK Foreign Secretary, Robin Cook, and the US Secretary of State, Madeleine Albright, said the "brutality" of President Slobodan Milosevic made them more determined than ever to continue the attacks.

Kevin Connolly reports on the legacy of the "human shield" bombings

And in the wake of the bombing of the village of Korisa in which more than 80 civilians were reported killed, they also warned that more civilian casualties could result from the Nato campaign as "perfection is unattainable".

(Click here to see a map of the most recent Nato strikes)

Serbian reports said Kosovo had experienced its heaviest attacks of the 54-day campaign.

Nato was also reported to have struck oil and power installations around Belgrade and other Serbian towns.

Nato says Kosovo experienced its heaviest attacks since the campaign began

The Yugoslav army has accused Nato of deliberately preventing their withdrawal from Kosovo.

They say the intensified attacks have made it "impossible" to carry out a planned withdrawal of part of their forces in Kosovo.

"It is obvious Nato ... is doing everything possible to prevent the withdrawal," an army statement said.

Nato dismissed the statement as "perverse".

Spokesman Jamie Shea said: "It's rather like an alcoholic blaming his problem on the whisky company".

Refugees denied food

Several hundred refugees from Kosovo who have arrived in Macedonia over the weekend say many of them were forced to leave because Serb forces would not allow them to buy food in the shops.

One woman told UN officials that her father had gone out to buy food and was later found shot dead.

Foreign Secretary Robin Cook: Ground troops have been considered from beginning

The groups arriving over the past two days were the first refugees to arrive in Macedonia since the government temporarily closed the border ten days ago saying it could not cope with a mass influx.

Reports say thousands more are waiting to cross from Kosovo.

UN team arrives

A UN team heading for Kosovo arrived in Belgrade on Sunday for the first part of its humanitarian mission to Yugoslavia.

The mission is made up of 16 people from the UN's main agencies as well as the British Save the Children Fund.

Mission spokesman, David Chikraidze, said the team, which would be escorted by Yugoslav police, had been assured access to some of the towns where refugees had spoken of systematic ethnic cleansing.

Italy unease grows

The Italian Prime Minister, Massimo D'Alema, is reported to be coming under serious pressure from parties in his ruling coalition to press Nato to halt air attacks on Yugoslavia with momentum growing for a vote in parliament this week.

Tens of thousands of people took part in a silent march from Perugia to Assisi in central Italy on Sunday to express their opposition to air strikes.

There has also been further criticism of the bombing campaign after Nato admitted dumping unexploded bombs into the Adriatic Sea.

Fishermen have found several in their nets off the coast of Venice.

• Serbs blamed for Nato killings
• Refugees say Serbs withhold food
• Embassy blame shifts to map agency
• Nato dumps bombs in Adriatic
• Blair on Balkan solidarity mission

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