PARIS, March 11 -- Slobodan Milosevic, the former Yugoslav leader who presided over the Balkan wars of the 1990s, was found dead Saturday in his cell at a United Nations prison near The Hague where he was on trial for war crimes, among them, genocide that became known to the world as "ethnic cleansing."

The 64-year-old Milosevic "was found lifeless on his bed in his cell at the United Nations Detention Unit in Scheveningen," said a statement from the U.N. tribunal. "The guard immediately alerted the Detention Unit Officer in command and the Medical Officer. The latter confirmed that Slobodan Milosevic was dead," the written statement said.

The tribunal statement said Dutch police and a Dutch coroner will launch a full investigation, including an autopsy and a toxicological examination to determine the cause of death."

Milosevic had been in poor health and his trial has been interrupted often because of his chronic heart condition.

Once an apparatchik in the Communist government of Josif Broz, better known as Marshall Tito, Milosevic converted to Serb nationalism after Tito's death in 1980 and became its most prominent firebrand as Yugoslavia broke into pieces and warfare.

He was elected president of Serbia in December, 1990 in its first multi-party election since World War II.

The former Yugoslav president was charged by UN prosecutors in May 1999, during the West's military intervention in Kosovo, with crimes against humanity stemming from what they said was a brutal campaign of violence and murder directed at the province's majority population of ethnic Albanian civilians. Later UN charges accused him of provoking genocide against non-Serbs in Croatia, Bosnia and Kosovo.

The trial was recessed last week to await Milosevic's next defense witness. A key witness who testified against Milosevic, a Croatian Serb leader named Milan Babic, committed suicide in his own cell a week ago, according to officials at the tribunal.

The two prominent deaths are likely to complicate international efforts to force the capture this year of two key Serbian wartime leaders -- Ratko Mladic and Radovan Karadzic -- for trial at the Hague. Both are suspected to be hiding among Serbs.

Dubbed the "Butcher of the Balkans" by his many enemies, Milosevic still maintained a remnant following among die-hard Serb nationalists. Those sentiments were reflected in the reaction Saturday to his death.

"What can I say," commented Vuk Draskovic, foreign minister of Serbia-Montenegro.

"Milosevic organized many many assassinations of people of my party, of people of my family. He ordered a few times assassination attempts against my life," he told wire services. "I can say it's a pity he didn't face justice in Belgrade."

"It's a pity that Milosevic did not live through the trial and get his deserved sentence," said a statement issued by the office of Croatian President Stjepan Mesic. "It's pity that Milosevic did not live through the trial and get his deserved sentence."

Former Balkans envoy David Owen said, "It's sad that justice in a way has been cheated. He was the first head of state to be given a trial, he's been given a very fair trial, it's taken an extraordinarily long time."

"I think people everywhere, but particularly in the former Yugoslavia and in Bosnia were wanting this verdict," Owen told wire services. "They now will feel cheated and it's a tragedy in a way that justice has not been able to give the verdict which we was important to hear."

Ivica Dacic, of Milosevic's Socialist Party, expressed a different view: "It's a big loss for Serbia and for the Socialist party. He was being systematically killed in the Hague and finally he died."

Milosevic's brother, Borislav Milosevic, said Slobodan "has a lot of supporters" among Serbs, "a lot of people who respect him. For them it will be a big blow," he told wire services. "I think that his memory will remain etched in history and everything he did for his country and for his people, resisting separatism and terrorism, and outside interference."

Milosevic, 64, and his pro-Serb, nationalist policies were a driving force behind a decade of ethnic wars in the Balkans. The conflicts broke Yugoslavia into five independent countries, caused the deaths of hundreds of thousands of civilians, and forced the most brutal population relocations in Europe since World War II.

The southeastern European region still bears the scars of his rule, with its citizenry still largely impoverished and its politics marked by corruption and enduring bitterness. Only the tiny republic of Montenegro remains joined to Serbia now, and its populace will vote later this spring on whether to become independent.

Kosovo remains under international control with a heavy presence of U.S. and European troops, but international officials say it is moving toward some form of permanent independence from Serbia, Milosevic's former base of support.

Milosevic, one of the most skilled and enduring Communist rulers on the continent, led the Serbs with a unique brand of opportunism, charm, ingenuity, and terror. He cleverly used the secret police to manipulate Serbian politics and repeatedly humiliate or undermine his opponents; he also, according to criminal charges brought after his ouster, ordered the assassination of several of his most feared political rivals.

He escaped local blame for years by claiming that the nation's isolation -- forced by UN sanctions -- and its economic setbacks were due to a Western-led campaign of anti-Serb persecution.

His ouster from office in a popular revolt in 2000 was engineered in part by youthful political dissidents who benefited from an infusion of Western cash and training, but it was sustained by military and political leaders who had become weary of his rule.

Milosevic's extradition to the Hague in April 2001 was itself engineered under Western pressure by a successor and longtime rival, prime minister Zoran Djindjic, who was assassinated by a secret police sniper in March 2003. Djindjic's killing brought more conservative leaders into power, and Serbia is now ruled by a diverse and fractious coalition that includes Milosevic's former Socialist Party.

The country is different today, however, and while the circumstances of Milosevic's death are likely to prompt renewed hostility to the tribunal, most Serbs are still keen to see their nation integrated with the West. The European Union has forced the country to initiate reforms that will eventually bring badly needed foreign investment and loosen travel restrictions.

Fred Barbash and R. Jeffrey Smith reported from Washington.