A NATO commander, Gen Wesley Clark, was locked in crisis talks with the Yugoslav leader, Mr Slobodan Milosevic, yesterday, backed by a renewed threat of force against Belgrade unless it softens its policy on Kosovo.
Gen Clark, accompanied by GenKlaus Naumann, head of the alliance's military committee, went straight to the US embassy on arrival in Belgrade for a briefing with the American head of international monitors in Kosovo, Mr William Walker, before beginning talks with President Milosevic.
NATO sources in Brussels said the two generals had completed an initial round of talks with the Yugoslav leader, and were due to return for more after a brief pause.
They discussed Yugoslavia's decision, announced on Monday, to expel Mr Walker, and Belgrade's refusal to allow the UN war crimes prosecutor, Ms Louise Arbour, to investigate an alleged massacre of ethnic Albanians at the weekend. Belgrade said the victims were armed guerrillas killed in the heat of battle.
The next topic on the agenda is the issue of Yugoslav compliance with a ceasefire accord negotiated last October, under the threat of air strikes, including limits on the number and posture of troops and special police in Kosovo. The Yugoslav government yesterday extended the expulsion order on Mr Walker by 24 hours. On Monday the veteran US diplomat, head of the Kosovo Verification Force, was given 48 hours to leave the country after he had publicly blamed Yugoslav security forces for the weekend massacre.
Ms Arbour was still waiting in neighbouring Macedonia yesterday after saying the Yugoslav Justice Ministry had told her there was no legal basis for her team to be allowed into Kosovo since what was taking place there was "terrorism", against which all countries were fighting.
Speaking by telephone, Ms Arbour told the independent Belgrade-based Beta news agency she would remain in Macedonia and await a decision on her movements.
Gen Clark warned before his arrival that punishment air strikes could be imminent, and Mr Milosevic should not doubt NATO's commitment to reaching a political solution in the troubled Serbian province.
"Trust me, this is going to be a very clear and a very blunt message," he told CNN television before leaving Brussels.
The US National Security Adviser, Mr Sandy Berger, said yesterday the threat of force was still a very strong option in Kosovo. Mr Berger said the two NATO generals would make it very clear to Mr Milosevic that he must comply with an October ceasefire brokered using the threat of air strikes. "If he is prepared to abrogate those agreements, NATO's plans are still very much on the table and the threat of force is very much an option."
In Moscow the Russian Foreign Minister, Mr Igor Ivanov, said Russia would oppose any military action by NATO in Kosovo to punish Belgrade for the massacre of 45 ethnic Albanians.
Mr Ivanov reiterated Moscow's traditional position that the only way to resolve tensions in the troubled Serbian province was by way of negotiations.
"We are convinced that military action would only increase tensions in Kosovo," Mr Ivanov said.
In Bonn the German Foreign Minister, Mr Joschka Fischer, also warned against military intervention, saying the situation was too serious for hasty action.
Mr Fischer rejected opposition charges that the government had not taken a clear enough position against Mr Milosevic. Mr Fischer told the German press agency (DPA) radio that Germany acted strongly in unison with its allies.
He said any decision would have to await the result of the meetings in Belgrade between Gen Clark and Mr Milosevic.
The head of a Finnish forensic team was expected in Belgrade last night, and was to go on to Kosovo later in the week, after being invited to take part in post-mortems on the victims of the weekend killings.
But Yugoslav and Belarussian forensic experts in the Kosovo capital, Pristina, having said they would wait until the Finnish team arrived before starting their examinations of the bodies, went ahead anyway yesterday.
"We have started. They [the Finns] will join in later and that does not jeopardise the job," a source at Pristina's Forensic Medical Institute told Reuters.
Ms Arbour had voiced her anger at a decision by Yugoslav authorities to bring the bodies to Pristina before they could be examined by outside experts.
The official Yugoslav news agency Tanjug said the team's initial examination had come up with no evidence of a massacre.
"The examination so far showed no signs of mutilation on the bodies of the terrorists, as Kosovo Verification Mission head William Walker had alleged in an extremely tendentious manner," it said.
Prof Sasa Dobricanin, director of the Pristina Forensic Medical Institute, has said he suspects the bodies might have been mutilated posthumously to make it look as if they had been executed.
The bodies, discovered in the southern village of Racak, were brought to Pristina hospital on Monday after two days of fighting over the village between Yugoslav security forces and ethnic Albanian guerrillas enraged by the killings.
The West, whose monitors counted 45 bodies in the village on Saturday, has accused Serbian police of a massacre. Serbian authorities have said the victims were guerrillas who died in clashes after opening fire on police.