As the speaker of the Cypriot parliament flew to Belgrade to secure the freedom of the three, Ivica Dacic, spokesman for the party led by President Slobodan Milosevic, said Yugoslavia had no knowledge of the mission announced on Wednesday.

Spyros Kyprianou was expected to arrived in Belgrade at 1350 GMT and then depart with the soldiers at 1700 GMT, according to US officials.

Spyros Kyprianou: "I will bring the three men to Cyprus"

The flight is due to land at Larnaka in Cyprus at 0030 GMT.

Pentagon spokesman Ken Bacon said airspace had been "deconflicted" by allied forces to allow the flight through.

Earlier, the Cypriot president said that Yugoslavia expected Nato bombing to ease if it turns over the detained Americans.

"It is only too evident that Yugoslavia has been upset by last night's heavy bombing," said the envoy before his departure from Athens.

"While the Americans could be released over the Orthodox Easter, Nato could reciprocate by responding to international appeals for a temporary ceasefire," said Mr Kyprianou.

One of his aides went further, saying the Serbs were demanding a full ceasefire.

America waits and hopes

Mr Kyprianou said he remained "very hopeful" he would be able to secure the release of the Americans following contacts with Greek, Russian and Yugoslav diplomats.

Mr Kyprianou announced on Wednesday that Yugoslav President Slobodan Milosevic had offered to hand the three men over to him.

Yugoslav government officials later played down expectations, saying they welcomed the offer of the Greek Cypriots to mediate, but added that it was too early to speak about the release of the soldiers.

There has been no word of the US soldiers since a statement from military authorities in Pristina that they could be charged with criminal offences, including espionage.

Threats of trial

The threee servicemen were captured on 1 April.

Yugoslavia says the men could face charges relating to spying.

But Nato says the men were on a non-combat patrol on the Macedonia-Kosovo border and has demanded they be treated as prisoners of war under the terms of the Geneva Convention.

Nicholas Witchell reports: "The signs of uncertainty have disappeared"

The three captive men, Steven Gonzales, Christopher Stone and Andrew Ramirez, are members of the 1,000-strong UN Preventative Deployment Force, Unpredep.

The force has patrolled the borders of Macedonia and Yugoslavia since the Bosnian war in 1993.