Former Palestinian leader Yasser Arafat died of natural causes and not radiation poisoning, the head of a Russian state forensics agency that tested samples taken from his body said.
The finding was in line with an assessment by French scientists who said earlier this month that Arafat, who died in 2004, had not been killed with radioactive polonium.
Swiss forensic experts said that their tests of samples taken from Arafat's body were consistent with polonium poisoning, while not absolute proof of the cause of death.
Samples were taken from Arafat's body in November 2012 by Swiss, French and Russian experts after an al Jazeera documentary said his clothes showed high amounts of polonium.
French forensic tests have concluded that Yasser Arafat did not die of poisoning, as had been suggested by an earlier report.
"The results of the analyses allow us to conclude that the death was not the result of poisoning," a source told Reuters quoting conclusions of a report by French forensic experts which has been passed to Arafat's widow Suha.
Last month the Palestinian leader's widow claimed he was poisoned to death in 2004 with radioactive polonium, after receiving the results of Swiss forensic tests on her husband's corpse.
Arafat died in a French hospital in November 2004, four weeks after falling ill.
The official cause of death was a massive stroke but French doctors said at the time they were unable to determine the origin of his illness and no autopsy was carried out.
The Swiss investigators who detected enough polonium in the body of Yasser Arafat to kill him say there should be an inquiry into how the former Palestinian leader died.
Many Palestinians agree, but Israel has dismissed the idea as a conspiracy theory.
ITV News Middle East Correspondent Geraint Vincent reports.
An expert in radioactivity measurements told ITV News that while he believes the scientists who concluded Arafat was poisoned did a "thorough and careful job" and considered factors that could impact their findings, the seven-year delay makes the statistical certainty of their conclusions "limited".
Hanan Ashrawi, who was close to Yasser Arafat and saw him shortly before he left for Paris has said that his illness looked "unnatural."
She said: "I talked to the medical teams that were examining him, they told me that unquestionably that he was poisoned, but they couldn't identify the poison."
Ms Ashrawi said that "we have to pursue now the people that are responsible justice has to be done."
The widow of Yasser Arafat, Suha, has described how weak the former Palestinian leader was before his death after it was revealed that scientists have found a high level of polonium 210 in his exhumed body.
Mrs Arafat said: "Words can't express my deep sorrow and the sorrow of my daughter, but mostly the anger - we are so angry. It's a political crime, a political assassination. It is so hard, we are mourning him again."
Video courtesy of Al Jazeera.
The Israeli government has denied any role in the death of Yasser Arafat, saying that he was 75-years-old.
"This is more soap opera than science, it is the latest episode in the soap in which Suha opposes Arafat's successors," Israeli Foreign Ministry spokesman Yigal Palmor said.
The investigation amounted to "a highly superficial attempt to determine a cause of death".
Suha Arafat, the widow of the late Palestinian leader said: "When they came with the results, I’m mourning Yasser again. It’s like you just told me he died. I will not stop. Me and my daughter will go to all courts in all over the world to punish who did this crime."
Some experts have questioned whether Arafat could have died of polonium poisoning, pointing to a brief recovery during his illness which is not consistent with radioactive exposure. They also noted he did not lose all of his hair.
But Professor David Barclay said neither fact was inconsistent with the findings.
Since polonium loses 50% of its radioactivity every four months, the traces in Arafat's corpse would have faded so far as to have become untraceable if the tests had been conducted a couple of years later, Professor Barclay said.