WASHINGTON – While Israel has formally refuted allegations it was involved in the assassination of Hizbullah 'operations officer' Imad Mugniyah in Damascus on Tuesday, former CIA official Bruce Riedel says all signs seem to indicate the Mossad was behind the killing.

Iran Blames Israel Iran: Mugniyah killing result of Israeli 'state terrorism' Roee Nahmias Tehran praises assassinated Hizbullah leader as 'golden page in the history of mankind's fight against Zionists.' Syria: Assassination a cowardly act of terror. Washington welcomes death of man on FBI's most wanted list, says world 'a better place' without Mugniyah Iran: Mugniyah killing result of Israeli 'state terrorism'

Riedel, who spent over 30 years with the CIA before serving as a senior advisor on South Asian and Middle East affairs under three US presidents, said Israel has already carried out similar operations in Syria.

Currently a senior fellow with the Saban Center for Middle East Policy at the Brookings Institute, he says Mugniyah's assassination proves Israel has successfully infiltrated Hizbullah and that even Secretary General Hassan Nasrallah knows he may also be in the crosshairs.

"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, "the Mossad is looking for Nasrallah and he knows it, that's why he conducts his operations from underground."

And the Hizbullah leader may have good reason to worry, said Riedel. "He's wondering who tipped off Mugniyah's location. That same individual could also reveal his own whereabouts."

When asked if the United States did not also have a stake in seeing the elimination of a man responsible for the deaths of American citizens, among them a senior CIA figure, Riedel said that while it was true Mugniyah was responsible for the murder of William Buckley "and that as far as we're concerned, he was

second only to Osama bin-Laden" – a car bombing was more consistent with the Mossad's modus operandi.

"In all honesty over the years we've become busy with many other issues, while ever since the summer of 2006 Hizbullah has returned to the forefront of Israel's concerns. Mugniyah also acted as a go-between with Iranian intelligence and Hamas."