A prize-winning Iranian nuclear scientist has died in mysterious circumstances, according to Radio Farda, which is funded by the U.S. State Department and broadcasts to Iran.

An intelligence source suggested that Ardeshire Hassanpour, 44, a nuclear physicist, had been assassinated by Mossad, the Israeli security service.

Hassanpour worked at a plant in Isfahan where uranium hexafluoride gas is produced. The gas is needed to enrich uranium in another plant at Natanz which has become the focus of concerns that Iran may be developing nuclear weapons.

According to Radio Farda, Iranian reports of Hassanpour’s death emerged on Jan. 21 after a delay of six days, giving the cause as “gas poisoning”. The Iranian reports did not say how or where Hassanpour was poisoned but his death was said to have been announced at a conference on nuclear safety.

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Rheva Bhalla of Stratfor, the U.S. intelligence company, claimed on Friday that Hassanpour had been targeted by Mossad and that there was “very strong intelligence” to suggest that he had been assassinated by the Israelis, who have repeatedly threatened to prevent Iran acquiring the bomb.

Hassanpour won Iran’s leading military research prize in 2004 and was awarded top prize at the Kharazmi international science festival in Iran last year.

President Mahmoud Ahmadinejad is expected to announce next Sunday — the 28th anniversary of the Islamic revolution — that 3,000 centrifuges have been installed at Natanz, enabling Iran to move closer to industrial scale uranium enrichment.

Inspectors from the International Atomic Energy Agency say that hundreds of technicians and laborers have been “working feverishly” to assemble equipment at the plant.

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