"Without concluding that this was an assassination, it fits in line with the kind of actions that have...deprived Iran of some of its top influential leadership" in nuclear and missile efforts, says Mark Fitzpatrick of the International Institute for Strategic Studies (IISS) in London. "Missiles are a major component of having a nuclear weapons capability, and this is the first time that we've seen some hint that the missile aspect is bearing the brunt," says Mr. Fitzpatrick, who edited a comprehensive 150-page dossier on Iran's ballistic missiles earlier this year.
The Islamic Republic insists its nuclear program is only to produce energy. Yet the latest report on Iran's efforts by the UN's watchdog International Atomic Energy Agency (IAEA), released last week, found a "systemic" effort by Iran to master weapons-related nuclear work, until it was halted in 2003.
Though some experts question the validity of the IAEA intelligence, the IAEA claimed that some weapons-related work "may" still continue.
The blast Saturday, 30 miles west of Tehran, was so large it could be heard and felt in the capital.
As Iran declared it would launch an investigation – and warned that any "foreign hand" would be met with revenge – one Western intelligence source credited Israel's Mossad intelligence service.
"Don't believe the Iranians that it was an accident," the unidentified Western source told Time in a report from Jerusalem. "There are more bullets in the magazine."
The Israeli government has been at the forefront of calls for military action to disrupt Iran's nuclear program. It does not accept the conclusions of a US National Intelligence Estimate (NIE) on Iran in late 2007 – and reportedly reaffirmed earlier this year – that Iran gave up its nuclear weapons work in the autumn of 2003, and has made no subsequent decision to go for a bomb.