Yasser Arafat died of natural causes, not radiation poisoning, Russian scientists who examined his remains said on Thursday, but their findings were dismissed by Swiss experts as politically motivated.
The conclusions into the Palestinian leader's 2004 death dovetail with the findings of French investigators but differ from those of Swiss radiation experts who maintain he could have been poisoned.
"We have completed all the studies," Vladimir Uiba, head of Russia's Federal Medical-Biological Agency (FMBA), told reporters.
"The person died a natural death and not from radiation."
The Palestinians have long suspected that Arafat was poisoned, with some pointing the finger directly at Israel.
Uiba said that his agency had not received any requests from the Palestinians to conduct a repeat examination.
"We've completed an expert evaluation, and everyone agreed with us. Moreover, even the Swiss withdrew their statements and agreed, and the French confirmed our conclusions," Uiba told reporters in comments confirmed by his spokesman.
The director of the Lausanne Radiophysics Institute who examined the samples of Arafat's remains, immediately took issue with Uiba's statement, saying the position of the Swiss experts had remained the same.
"Our point of view has not changed, that's for sure," said Francois Bochud, criticising the Russian experts for not releasing their report.
"The Russians, they make claims without providing any data, without providing any scientific arguments, for me that is empty, a political declaration."
Bochud said the Swiss had not received a copy of the Russian study, and that Palestinian officials who had seen it said the results were similar to the Swiss data.
"But to claim the opposite with same data seems to be really fallacious," he said.
Bochud co-authored a report released in November that found high levels of polonium, up to 20 times the normal level, were found in samples taken from Arafat's body. The report said the findings were consistent with radioactive poisoning without saying conclusively Arafat's death was due to the polonium.
Alexander Vlasov, the spokesman for the Federal Medical-Biological Agency, told AFP the Russian experts had been tasked by the foreign ministry to carry out the investigation for the Palestinian authorities.
He said it was up to the Palestinians to publish the report.
The Palestinian ambassador to Russia said the Palestinian authorities would press on with the probe.
"I can only say that there is already a decision to continue (the investigation)," Faed Mustafa told the state RIA Novosti news agency.
"We respect their position, we highly value their work but there is a decision to continue work," he said. "We need a result, a final and concrete result to take the issue off the table."
Mustafa was not available for further comment on Thursday.
A decision to ask the UN General Assembly to establish an international commission to investigate the circumstances of Arafat's death was taken at an Arab League meeting in Cairo on Saturday.
'Russia has no stakes in this game'
Arafat died in France on November 11, 2004 at the age of 75, but doctors were unable to specify the cause of death. No autopsy was carried out at the time, in line with his widow's request.
His remains were exhumed in November 2012, partly to investigate whether he had been poisoned with radioactive polonium, a suspicion that grew after the substance was used to assassinate Russian ex-spy and Kremlin critic Alexander Litvinenko in 2006.
Some 60 samples were taken and divided between Swiss and Russian investigators as well as a French team carrying out the probe at the request of Arafat's widow, Suha. The French have also ruled out radioactive poisoning.
Suha Arafat has told AFP that she was "completely convinced that the martyr Arafat did not die a natural death."
Fyodor Lukyanov, head of the Kremlin-friendly Council on Foreign and Defence Policy, said he saw no reason for the Russian experts to distort the results of their findings.
"At the time of his death Arafat was no longer a figure defining Palestine-Israeli relations. Russia has no stakes whatsoever in this game."