Palestinian Authority President Mahmoud Abbas cleared the way Wednesday for a possible autopsy on the late Palestinian leader Yasser Arafat's remains.

Arafat’s widow, Suha Arafat, requested the autopsy after a Swiss lab said it had found elevated levels of a lethal radioactive isotope on Arafat’s belongings.

The developments have reignited a storm of speculation over the cause of Arafat’s death on Nov. 11, 2004, at the age of 75 at a military hospital outside Paris.

Suha Arafat, who rejected an autopsy at the time of her husband’s death, said she wanted one done now in the wake of the lab's findings. Her request was first reported by the Arab satellite TV station Al-Jazeera. In an interview with the station, she did not explain why she waited nearly eight years to have Arafat’s belongings, including a toothbrush and a fur hat, tested.

French doctors said at the time that Arafat died of a massive brain hemorrhage, weeks after he fell violently ill at his West Bank compound. He suffered intestinal inflammation, jaundice and a blood condition known as disseminated intravascular coagulation, according to French medical records.

But the records were inconclusive ast to what brought about the coagulation, which can have numerous causes including infections, colitis and liver disease. Outside experts who reviewed the records on behalf of The Associated Press were also unable to pinpoint the underlying cause.

The uncertainty prompted many in the Arab world to allege he was killed by Israel, which viewed him as an obstacle to a peace treaty. Israeli officials have vociferously denied any foul play.

Israeli Foreign Ministry spokesman Yigal Palmor was dismissive of the latest developments, saying, "The circumstances of Mr. Arafat's death aren't a mystery ... He was treated in France, in a French hospital, by French doctors, and they have all the medical information."

Francois Bochud, who heads the Institute of Radiation Physics in Lausanne, Switzerland, told AP on Wednesday that his lab had examined belongings that Suha Arafat had claimed were used by her husband in his final days, as well as other items that he had not worn.

Suha Arafat said the items were kept in a secure room at her attorney's office in Paris after Arafat's death and stayed there until Al-Jazeera approached the lab on her behalf at the beginning of this year, he added.

Experts found what Bochud characterized as "very small" quantities of polonium, an isotope naturally present in the environment. There were higher quantities of polonium on clothing Arafat had worn, including urine-stained underwear and bloodstained hospital clothing, than on belongings he had not used, such as new and unworn socks stored in the same bag.

Polonium is best known for causing the death of Alexander Litvinenko, a one-time KGB agent turned critic of the Russian government, in London in 2006. Litvinenko ingested tea laced with the substance.

Bochud said an "elevated" level of more than 100 millibecquerels, a measurement of radioactivity, was found on belongings used by Arafat, compared with 10 millibecquerels in the reference samples.

He said this would not necessarily mean Arafat had been poisoned, and it was not possible to say where the polonium might have originated.

"What is possible to say is that we have an unexplained level of polonium, so this clearly goes toward the hypothesis of a poisoning, but our results are clearly not a proof of any poisoning," Bochud said by telephone from Switzerland.

Denis Gutierrez, a senior French military doctor, said he did not know whether French medics had checked Arafat for polonium while he was at France's Percy military hospital, and was unaware of anything about poisoning in the 558-page classified report on his death.

But Gutierrez said nothing had been sent from the hospital to the Swiss lab, raising questions about the reliability of the belongings that were tested.

"Samples taken in the hospital remain in the hospital," he said.

Even if further testing does take place, the mystery surrounding Arafat's death may never be solved.

Alastair Hay, professor of environmental toxicology at the University of Leeds in England, said bone marrow and hair samples should be tested for signs of poisoning.

"You don't know much about the provenance of the clothing and whether it had been tampered with later on. You'd want to test the body," he said.

But Bochud said Arafat's medical records showed that, unlike Litvinenko, Arafat’s bone marrow had been in good shape and he had not lost his hair. In addition, Arafat's condition in the French hospital briefly improved before sharply deteriorating in his final days. Such improvement might contradict poisoning as a cause. In any case, polonium breaks down relatively quickly, meaning that after eight years, much of any polonium that was there would be gone.

At the time of his death, Arafat was confined by Israel in the Ramallah government compound. The U.S. and Israel viewed Arafat as largely responsible for the outbreak of the second Palestinian uprising.

In a radio interview, Dov Weisglass, the chief of staff of Israel's then-Prime Minister Ariel Sharon, insisted that Israeli officials never considered killing Arafat and, in fact, Sharon had opposed the idea because "he didn't think his physical extermination would help. On the contrary."