Nikolay Dobryukha, described as a historian and publicist, said documents of medical examinations of Stalin disprove the official cause of death as a cerebral hemorrhage caused by hypertension and arteriosclerosis, Pravda reported on its Web site.

Stalin died March 5, 1953, at age 73 after a dinner with several other Soviet officials, including Interior Minister Lavrenty Beria. Stalin was said to have collapsed in his room but guards, under orders not to disturb him, did not find the Soviet leader until the next night. He died four days later. A memoir by Vyacheslav Molotov claimed Beria boasted of having poisoned Stalin.

The report this week on Pravda says doctors' journals from treating Stalin say on March 5, results of blood and urine tests indicated poisoning but the doctors feared telling Beria of the finding because he might think the doctors poisoned the leader, Pravda said.

Stalin led the Soviet Union from the last 1920s until his death in 1953. While he is credited with building a force that helped defeat Germany in World War II, he is also known for draconian rule that caused the deaths of millions of Russians.