``We made no headway,'' a senior diplomat said after NATO Commander General Wesley Clark met Yugoslav President Slobodan Milosevic at Belgrade yesterday.

Ratcheting up the US' warnings, President Bill Clinton today said, ``With our NATO allies we are pressing the Serbian government to stop its brutal repression in Kosovo, to bring those responsible to justice and give the people of Kosovo the self-government they deserve.''

His comments came after US officials stepped up their warnings to Milosevic over Kosovo, laying down four demands for the threat of air strikes to be lifted.

Meanwhile, the UN Security Council has condemned the massacre of 45 ethnic Albanians and demanded immediate investigation into thekillings.

In a presidential statement read out at an open meeting late last night, the Council deplored Yugoslavia's decision to block the entry of UN war crimes tribunal prosecutor Louise Arbour from entering Kosovo and Belgrade's decision to expel William Walker of the US who headed the 800-strong team of international monitors there.

However, though State Department spokesman James Rubin asserted that no decision about whether to move toward air strikes had been taken, Secretary of State Madeleine Albright said yesterday the ``military activation order is on the table. It is effective.''

Meanwhile, head of the Yugoslav forensic team examining the bodies of 40 ethnic Albanians, believed to have been slaughtered by Serb police, said they bore no signs of having been massacred, reports said.

Yugoslav and Belarussian forensic experts yesterday examined the bodies of the villagers from southern Kosovo killed last Saturday.

The Security Council asked Belgrade to cooperate fully with the tribunal set upto try war crimes.

The Security Council statement came after hours of negotiations during which Russia tried to block mention about investigation by the Hague-based tribunal.

The United States and France would have liked the Council to demand that Arbour be allowed in Kosovo but apparently agreed to leave that out to get consensus without which the statement could not have been issued.

The statement noted that international monitors had blamed Serbian forces for the massacre.

The four demands delivered to Milosevic yesterday were reversing the decision to expel Walker, allow UN war crime investigators to probe the massacre, identification of the perpetrators of the massacre and reversal of last October's cease-fire agreement.

Meanwhile, Albanian Prime Minister Pandeli Majko has urged Clinton to back military intervention in Kosovo to prevent a regional war in the Balkans, the Albanian government said.

1``As you know, Belgrade has intensified its repression of the Albanian population in Kosovo,provoking the explosion of wider Balkan conflict,'' Majko said in a letter to Clinton.