NATO'S threat to bomb Yugoslavia is hanging in the balance as the US envoy, Mr Richard Holbrooke, and the Yugoslav President, Mr Slobodan Milo sevic, broke off crisis talks on Kosovo last night with no word on the outcome.
The talks, in which Mr Holbrooke was making an 11th-hour attempt to persuade Mr Milosevic to halt an offensive against Kosovo Albanian separatists, who have already accepted a peace plan, ended at 10.15 p.m. (9.15 p.m. Irish time) after almost four hours.
The White House has instructed Mr Holbrooke to meet Mr Milosevic again in an effort to persuade him to sign a peace deal.
"They will talk again tonight," a White House aide said on condition of anonymity, adding that "it could be by phone".
CBS television reported that a senior White House official said there had been no sign of progress all day long and quoted sources as saying Mr Holbrooke's mission ended with "not very promising" results.
Fighting continued to rage in Kosovo, with the Serbs continuing a week-long offensive and NATO repeating warnings that it will bomb unless the shooting stops.
"We think this is the moment of truth," said NATO's Secretary-General, Mr Javier Solana.
President Clinton said he had written to President Yeltsin of Russia about "the urgency of the situation". But he did not disclose what was in the letter.
The Russian Prime Minister, Mr Yevgeny Primakov, is due to arrive in Washington today for discussions with President Clinton and there has been speculation that any air strikes would be held back until after the visit.
President Clinton said yesterday that "only President Milo sevic and Serbia stand in the way of peace".
But Mr Milosevic went on national television last night with a defiant reply to an Anglo-French call for restraint.
"You are saying there are extensive movements of our security forces that are very worrying," he said. "If you think they are worrying for the separatists they should be, and if they worry any possible aggressors from the outside they should do that as well."
Meanwhile, NATO continued its military preparations, with a force of 430 strike aircraft assembling at air bases in Italy and on an aircraft carrier in the Adriatic.
The United Nations said fighting in Kosovo was now creating a critical refugee situation, with more and more villagers fleeing their homes into mountains now buried under deep snow.
Diplomats say that Thursday is pencilled in for the opening of the air bombardment, which would be by 430 aircraft based mostly in Italy and aboard a US aircraft carrier in the Adriatic. A final NATO meeting is expected to be held tomorrow to give the air-strike go-ahead.
Mr Holbrooke is under pressure not just to achieve a second ceasefire promise, but to find some way of ensuring Mr Milosevic sticks to it.
One chink of light came yesterday with the surprise announcement that Yugoslav forces were in fact ready to pull back - providing, said a defence ministry statement, that rebels of the Kosovo Liberation Army did the same.