BRUSSELS, March 12 (Xinhuanet) -- Former Yugoslav President Slobodan Milosevic said he feared being poisoned just one day before his death, his legal advisor Zdenko Tomanovic said on Sunday.

    Milosevic wrote a six-page letter to Russia one day before he was found dead, claiming that traces of a "heavy drug" had been found in his blood and that he was suspicious of being poisoned, said Tomanovic, who showed a copy of the letter to journalists at The Hague-based UN war crimes tribunal.

    "They would like to poison me. I'm seriously concerned and worried," the letter read.

    It alleged that a powerful drug used to treat leprosy or tuberculosis had been found in his blood during an examination on Jan. 12.

    "The persons who are giving me the drug for the treatment of leprosy surely can not be treating me, and especially those persons from whom I defended my country in the war and who also have an interest in silencing me can likewise not be treating me," read Tomanovic from an English translation of the letter.

    The letter, dated March 10, was addressed to the Russian Embassy and it asked to be forwarded to Russian Foreign Minister Sergei Lavrov.

    "I am writing to you and asking you for help and protection from the criminal activity perpetrated in the institution operating under the sign of the United Nations organization," Tomanovic quoted the letter as saying.

    Carla del Ponte, chief prosecutor of the International Criminal Tribunal for the former Yugoslavia (ICTY), said on Sunday that medical checks on Milosevic were thorough.

    "It is very strange, even if it is of course possible, that he should have died so suddenly without the medics having noticed a worsening of his condition," she said.

    Milosevic either committed suicide or died naturally as his trial for war crimes and genocide neared an end, she said.

    UN war crimes tribunal president Fausto Pocar said Sunday that the cause of Milosevic's sudden death remains unknown after a Dutch forensic team failed to determine it.

    Mirjana Markovic, wife of Milosevic, accused The Hague tribunal of killing her husband. Milosevic's elder brother Borislav said in Moscow that the tribunal must be held responsible for his brother's death.

    The authorities hope an autopsy will put to rest claims that Milosevic was murdered.

    Milosevic had appealed to the UN tribunal last December to be allowed to go to a heart clinic in Moscow for treatment, but the request was denied.

    The 64-year-old former president was found dead on Saturday morning in his cell at the international criminal court, prompting criticism of the tribunal from Milosevic's family and the Serbian press. Enditem