RAMALLAH: Swiss scientists have concluded Palestinian leader Yasser Arafat is likely to have died from polonium poisoning, according to a text of their findings published by Al-Jazeera television Wednesday.

The results of tests on Arafat's remains “moderately support the proposition that the death was the consequence of poisoning with polonium-210,” said the 108-page analysis posted on Al-Jazeera's website.

“New toxicological and radio-toxicological investigations were performed, demonstrating unexpectedly high levels of polonium-210 and lead-210 activity in many of the analysed specimens,” said the report penned by 10 experts at the Vaudois University Hospital Centre (CHUV).

It added that polonium levels in “bones and soft tissues were up to 20 times larger” than hypothesised, firmly ruling out the possibility previously reported in some media that passive smoking had caused greater than normal polonium levels on Arafat's personal effects.

Arafat's widow Suha said in an interview aired by Al-Jazeera that the poisoning, if proved, amounted to “the assassination of a great leader” and a “political crime.” “I don't know who did it, but it's terrible,” she said.

The Palestinian official in charge of the investigation into Arafat's death, Tawfiq Tirawi, said on Tuesday that he had received the findings of the Swiss laboratory, although he declined to disclose them.

Official Palestinian news agency WAFA said that a separate Russian team appointed by the Palestinian Authority also handed in its report on November 2.

Reacting to the Al-Jazeera report, a Palestinian source close to the investigation told AFP that “the report contained information about high levels of polonium in the specimen that was tested,” but gave no further details.

Some 60 samples were taken from the remains of the late Palestinian leader in November last year for a probe into whether he was poisoned by polonium.

The samples were divided between the Swiss and Russian investigators and a French team carrying out a probe at the request of Arafat's widow.

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 and samples taken, partly to investigate whether he had been poisoned – a suspicion that grew after the assassination of Russian ex-spy and Kremlin critic Alexander Litvinenko in 2006.

In an October report published by The Lancet, eight scientists working at the Institute of Radiation Physics and University Centre of Legal Medicine in Lausanne confirmed they found traces of polonium in separate tests on clothing used by Arafat which they said “support the possibility” he was poisoned.

Polonium is a highly radioactive material rarely found outside military and scientific circles.

Small doses exist in the soil and atmosphere, and even in the human body, but in high doses it is highly toxic if it is ingested or inhaled, and can damage the body's tissues and organs.

It is one of the rarest natural elements – in 10 grams of uranium ore there is a maximum of a billionth of a gram of polonium. Polonium-210 is the least rare of its 33 known isotopes.

The substance has been used industrially for its alpha radiation in research and medicine, and as a heating source for space components, but in those forms it is not conducive to easy poisoning.