The US has firmly rejected the Yugoslav unilateral ceasefire as insufficient to stop the NATO air strikes. The Yugoslav move had been anticipated by Washington as the NATO bombing intensifies.
The absence of any reference to a NATO-led international force to protect returning Kosovan refugees in the Yugoslav announcement was immediately criticised here as falling short of the conditions for ending the NATO air strikes.
The Secretary of Defence, Mr William Cohen, said the Serb ceasefire idea was "not only completely unacceptable but it's absurd". He said that accepting a ceasefire now would be an "abdication of responsibility" by NATO.
Later Mr Cohen, accompanied by a high-level Congressional delegation, flew to NATO headquarters in Brussels for consultations with the other countries making up Operation Allied Force.
President Clinton, speaking shortly before the announcement of the ceasefire in Belgrade, made it clear that President Milosevic must accept all the conditions laid down for ending the bombing.
"Mr Milosevic could end it now by withdrawing his military police and paramilitary forces, by accepting the deployment of an international security force to protect not only the Kosovar Albanians - most but not all of them are Muslims - but also the Serbian minority in Kosovo," the President said at a White House ceremony.
On Monday he had warned President Milosevic that "more empty promises and token half-measures won't do the job".
Pressure has been growing in the US for President Clinton to send ground troops into Kosovo to back up the air strikes which have not been able to prevent the expulsion of the Kosovan population. While the Administration insists that there is no intention to send in ground troops, a Washington Post-ABC poll yesterday shows that 55 per cent of Americans say they would support President Clinton if he did this.
The US has confirmed that the 20,000 refugees it has agreed to accept will be housed at its naval base in Guantanamo, Cuba, where refugees fleeing Haiti were held several years ago.
Secretary of State Ms Madeleine Albright also took a tough line on Kosovo when speaking at the Brookings Institute before the announcement of the Serb cease-fire.
"We are going to continue in this intensive air campaign and we will do so until all the Serb forces are out of Kosovo, hundreds of thousands of ethnic Albanian refugees are returned to their homes and Milosevic consents to a peace plan that would station a NATO peacekeeping force in Kosovo," she said.
Reuters adds:
NATO's military leader acknowledged in an interview published in Paris yesterday that air strikes could not prevent Serb atrocities in Kosovo but said the bombing would go on until the oppression ended.
US General Wesley Clark, NATO's supreme commander, said Serbian soldiers in Kosovo were worn down and tired but still capable of "terrible atrocities against civilians".
"I cannot say how long they can hold on," he told the Catholic daily La Croix, adding that NATO strikes would go on as long as the alliance needed to attain its goals.
"Air strikes alone are not enough to prevent the worst atrocities. That will not work. On the other hand, we are able to attack the installations and units used by the Serbs for their oppressive actions. And that is what we are doing.
"We are attacking and systematically destroying their command and control centres, their anti-aircraft defences and their capacity to attack the people of Kosovo."
Asked whether introducing NATO ground troops into the conflict could turn the tide, Gen Clark said this was up to the alliance's political leaders rather than NATO military chiefs.
Queried about the morality of bombing over the Easter holiday, he said his conscience was bothered by the plight of ethnic Albanian refugees forced to flee to Macedonia and Albania to escape Serb attacks in Kosovo.
"Christian theology - and I am Christian - says that all people, whether they are Muslim, Christian or non-believers, are the children of God and should be treated in the same way."
About 90 members of the Yugoslav army have gone on trial for attempting to desert the armed forces or lay down their arms, according to the German Defence Minister, Mr Rudolf Scharping.
"People who apparently tried to oppose Yugoslav army actions" have also gone on trial, he told a press conference in Bonn.
Mr Scharping said accounts were also emerging of what he called isolated cases in which Yugoslav army units had "acted properly [toward Kosovo Albanians] and tried to help them in some cases, giving them food and water".
"Yugoslavia is having problems recruiting new soldiers," he added.