Slobodan Milosevic knew Bosnian Serbs planned to massacre Muslims in Srebrenica in 1995, ex-Nato commander Wesley Clark told The Hague tribunal in evidence prosecutors said yesterday was central to their case.

Mr Clark, a US Democratic presidential hopeful who helped negotiate the Dayton accord that ended the Bosnian war, told Milosevic's war crimes trial he discussed the July 1995 massacre of 7,000 Muslim men and boys with Mr Milosevic a month after it happened.

The ex-Yugoslav president, charged with genocide, crimes against humanity and war crimes in Croatia, Bosnia and Kosovo in the 1990s, denied he had spoken to Clark about the atrocity, Europe's worst since WWII.

The 62-year-old former Serb strongman dismissed the testimony as a "blatant lie," saying he had been a peacemaker in the Balkans.

More than 200 pages of transcripts of Mr Clark's testimony were posted on the UN war crimes tribunal's website after the retired four-star general gave evidence behind closed doors on Monday and Tuesday at the request of the United States.

US peace negotiators trying to establish if they should deal with the Bosnian Serbs or Serbian leadership to hammer out a peace deal to end the 1992-95 Bosnian war were told by Mr Milosevic in 1995 to deal directly with him, Mr Clark said.

"I said, 'Mr President, you say you have so much influence over the Bosnian Serbs, but how is it then, if you have such influence, that you allowed General (Ratko) Mladic to kill all those people in Srebrenica?" Mr Clark said.

"And Milosevic looked at me and paused for a moment. He then said, 'Well, General Clark,' he said, 'I warned Mladic not to do this, but he didn't listen to me,'" Mr Clark said.

"It was very clear what I was asking was about the massacre at Srebrenica. When I said 'kill all these people,' it wasn't a military operation, it was a massacre... It was also, to me, very clear what Milosevic was answering," Mr Clark said.