According to Radio Farda, Iranian reports of Hassanpour’s death emerged on January 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.

Rheva Bhalla of Stratfor, the US 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.