The chief prosecutor of the United Nations War Crimes Tribunal in The Hague says one of the tribunal's most wanted suspects, Radovan Karadzic, is living in the Serbian capital, Belgrade. But the prosecutor's statement has been condemned in Serbia.

U.N. Chief Prosecutor Carla Del Ponte said Wednesday she received information from what she called a "credible source" that Belgrade has become a "safe heaven" for former Bosnian Serb President Radovan Karadzic and more than a dozen other fugitives.

She earlier announced that Mr. Karadzic's military adviser, General Ratko Mladic, is also hiding in Serbia with support from the Serbian military.

Both men are accused of supervising Europe's worst single atrocity since World War II during the ethnic conflicts in the 1990s which tore apart Yugoslavia.

The atrocity took place in 1995 in the Bosnian town of Srebrenica, where investigators say Serb forces killed up to 8,000 Muslim men and boys.

Ms. Del Ponte said the "most high level people" allegedly responsible for war crimes are now in Serbia, and she stressed that her office has frozen its relations with the Serbian government.

Some Balkan analysts say Mr. Karadzic likely arrived in Belgrade in January during a massive NATO manhunt designed to catch him.

Serbian officials said prosecutor Del Ponte should provide an address for Mr. Karadzic and others allegedly hiding in Belgrade, a city of about 1.5 million residents.

Outgoing Serbian Prime Minister Zoran Zivkovic told reporters that Ms. Del Ponte has never provided any information or other help which could lead to the arrest of war crimes suspects.

The Serbian interior ministry added that Serbia has no information that could confirm her claims.

The United States and the European Union have made it clear that the transfer of suspects to the War Crimes Tribunal in The Hague is a key condition for the release of multi-million dollar aid packages for Serbia, which needs the help after a decade of wars and ethnic strife.