A former CIA official has said that all signs seem to indicate that Mossad was behind the assassination of the top Hezbollah commander.

Imad Mugniyah, the senior Hezbollah commander in resistance operations against invading Zionist forces, was killed in a blast in Damascus on Tuesday.

Bruce Riedel said Israel has already carried out similar operations in Syria, according to Ynetnews.

Riedel spent over 30 years with the CIA before serving as a senior advisor on South Asian and Middle East affairs under three US presidents.

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Currently a senior fellow with the Saban Center for Middle East Policy at the Brookings Institute, he says Mugniyah's assassination proves the Zionist regime has infiltrated Hezbollah.

"Israeli intelligence services have motive and they have proven their ability to strike in Damascus in the past. This is a significant operation, whether or not the Israelis want to publicly admit to it. He (Mugniyah) has topped the US and Israel's most-wanted list for a quarter of a century," said Riedel.

The seasoned intelligence official said he believes Mugniyah was not the only name on a possible hit list. "It definitely includes Hassan Nasrallah," he said.