Mr Cook met Mrs Albright in Washington last week during a brief visit to discuss the conflict in the Balkans.

He told the BBC's Breakfast With Frost programme: "There is no rift between the US and the UK. We are solidly behind our objectives which is to get the Serbs out of Kosovo, get Nato into Kosovo and get the refugees back into Kosovo.

"What we now need to do is to build on the success of the air campaign and are ready to take advantage of it when the time comes to take the refugees back

Robin Cook: "We are talking a substantial military force which can provide real security and reassurance for the refugees"

"And on that I am pleased to say that while I was there Madeleine Albright did say that we should go ahead with our plans so that we can deploy our troops in a permissive or non-permissive environment."

More troops

Mr Cook said Nato had been asked to bolster its forces in the Balkans to about 40,000 troops.

He said when it entered Kosovo it would be "more than a peacekeeping force".

Mr Cook said: "We're not talking about people in blue helmets with light side arms.

"It would be a substantial military force capable of providing real security and reassurance to the people of Kosovo, because without that the refugees won't go back."

US troops fortify the Rinas airbase in Albania

Mr Cook said reports of a mutiny by a Serbian battalion in Kosovo showed the low morale among Yugoslav forces, and he said a third of their weapons had been destroyed along with half their ammunition.

He said: "As they get weaker, we're getting stronger."

Mr Cook denied the air campaign had taken longer than was envisaged.

He said: "We always knew it was going to be a long haul, but we have got the stomach for it."

He gave an individual anecdote to emphasise his point.

"There is a refugee now in Britain who left her home in an advanced state of pregnancy.

Robin Cook: "We've got to have the stomach to continue and finish the job"

"She walked for a week holding her youngest son and then she gave birth to another child on the road.

"Then she got up from childbirth and walked on until she got to Macedonia.

'Got to finish the job'

"You can only speculate on the terror that drove a woman to do that.

"If she has got the stomach and strength to do that then we really ought to have the stomach to continue and not say eight weeks is too long.

"We've got to finish the job so she and the hundreds of thousands like her can got back to their homes in safety."

Foreign Office Minister Tony Lloyd: "This does not represent a hardening of the language"

Foreign Office Minister Tony Lloyd later sought to clarify Nato's position.

He said Mr Cook's comments did not represent a "hardening of the language".

Mr Lloyd said: "Nato planners are examining all options and that means all options that are practical in bringing the conflict to an end and getting the refugees home securely."

'No decision yet'

But he said no final political decision had been made on the military options.

Former Deputy Prime Minister Michael Heseltine has also backed the deployment of ground troops in the Balkans.

Mr Heseltine, a former Defence Secretary, told GMTV the threat of invasion would psychologically weaken Serbia's President Slobodan Milosevic.