Nato Secretary General Javier Solana said air strikes on Yugoslavia have been suspended after confirming President Slobodan Milosevic had complied with Nato's five demands for ending the conflict.

Yugoslavia agreed to a full military withdrawal from Kosovo on Wednesday, after five days of talks between Nato and Yugoslav generals.

Mr Blair is expected to make his statement around 1500 BST from Downing Street.

A full withdrawal of Yugoslav troops has already begun from Kosovo.

Robin Cook: We don't want a security vacuum

UK forces will be among the first to cross the border into Kosovo as part of the deployment of the international force which will return the refugees home.

Robin Cook: A phased programme will follow troop withdrawal

As Serb forces left the province, international troops would take their place in a phased programme, the foreign secretary said.

"We are very keen that the moment the Serb forces are withdrawing from the sector opposite us across the border in Macedonia that we start to move in.

"The reason for that we don't want a security vacuum.

"We want our forces to go in there to secure the peace, secure the territory and start to create the conditions in which the refugees can go back so that there is no gap between one force leaving and one force going in."

The possibility of a Nato military campaign against Serbia would remain until the last of the troops had left Kosovo, he warned.

Mr Cook said Nato would be alert for any "trick" President Milosevic could pull, but said the Serb leader was now in a much weaker position.

Lt Gen Sir Michael Jackson: Preparing to take troops in

At the Ministry of Defence briefing Defence Secretary George Robinson said the agreement was a victory Nato could be proud of.

He said: "I believe Nato is on the way to accomplishing a great deed.

"The alliance has been prepared to go out of its way to fight for a downtrodden people against a campaign of ethnic hatred and it has won, and that, I think, is something we can all be proud of at the end of what has been a dark and difficult 20th century.

"This is a victory for the determination and resolve of the alliance to face down the kind of ethnic violence which has marred our century."

Nato had endured and prevailed, he continued.

"I hope Kosovo will send a stark message to those who see repression and ethnic violence as the acceptable tools of power that once the west has set its hand to action it does not stop until it has succeeded."

He paid tribute to the armed forces "who were prepared to risk their lives so other could live in peace".

But for General Jackson and his forces the difficult days were just beginning, said Mr Robertson.

They would encounter attacks by "wayward individuals", minefields and cope with the "tide of human misery and starvation left behind by the Serbs".