The United Nations War Crimes Tribunal says former Yugoslav President Slobodan Milosevic did not die of poisoning.  The announcement came Friday amid growing concern in Serbia over the circumstances surrounding his death in a Dutch prison cell.

Judge Fausto Pocar, center, and registrar Hans Holthuis, rear, at end of  press conference in The Hague

Speaking to reporters, the president of the UN War Crimes Tribunal, Fausto Pocar, said experts have found no evidence that Milosevic was poisoned or took an overdose of medicine.

"A toxicological examination was carried out after the autopsy resulting in the following provisional findings: So far no indications of poisoning have been found," he said.  "A number of medicines prescribed for Mr. Milosevic were found in the body material, but not in toxic concentrations."

Milosevic died last week at the age of 64 in a prison cell in the Dutch town of Scheveningen, outside the U.N. court in The Hague, where he was on trial for alleged war crimes during Balkan conflicts of the 1990s.

Slobodan Milosevic (2000 file photo)

Earlier, Russia's top cardiologist, Leo Bokeria, who headed a Russian team of doctors who were assisting Dutch pathologists, said Milosevic was not poisoned, but died of a heart attack.

"There were no typical signs which might be showing the poisoning," he said.  "So at the moment this preliminary diagnosis looks like I mentioned."

However, Dr. Bokeria and other officials have suggested that better medical treatment within the U.N. detention facility could have prevented the death of Milosevic, who was known to suffer from heart troubles and a high blood pressure. Shortly before he died, the former leader had sought medical treatment in Russia, which the U.N. did not approve amid fears he would not return.

Serbian President Boris Tadic said earlier this week that Milosevic's death had in his words undermined the credibility of the U.N. Tribunal.  Mr. Tadic did not allow a state funeral for Milosevic, who was known as the butcher of the Balkans, because he oversaw the bloody disintegration of Yugoslavia in which an estimated 250,000 people died.

Yet, he still has his supporters.  On Thursday and Friday, during a ceremony in Belgrade, a few thousand supporters filed passed his coffin, which was draped in the Serbian flag and covered with roses.

Mira Markovic (2002 file photo)

Meanwhile, Russian Communist Party chief Gennadi Zyuganov told reporters the former president's widow, Mira Markovic, lacks sufficient security guarantees and will not be present for the funeral.  A Serbian court had suspended an arrest warrant for her on charges of abuse of power, but authorities said they would still require her to surrender her passport and appear before a judge.

While there were emotional scenes among Milosevic's supporters, his opponents on Friday printed a hard-hitting memorial message in Serbia's Politika newspaper; it was next to a traditional death announcement, which praised the late leader. In the message they blame Milosevic for what they call his deceit and theft and for every drop of blood shed by thousands.  They also recall what they described as the horrors and wars he waged in the name of Serbs.