The man ordered by al Qaeda's branch in Yemen to blow up a US-bound airliner was a double agent who infiltrated the group and volunteered for the suicide attack, US media reported.
American officials leaked out details of the extraordinary intelligence coup two days after the White House announced a plot by al Qaeda in the Arabian Peninsula (AQAP) had been successfully thwarted.
The double agent managed to spend weeks with AQAP before handing over information that allowed the US to launch a drone strike on Sunday that killed Fahd al-Quso, a senior figure who was wanted for the 2000 bombing of the USS Cole in Yemen, the New York Times and other media reported, citing unnamed US officials.A senior US official told the Times that a bomb for the would-be attack was sewn into "custom fit" underwear that would have been difficult to detect even in a careful pat-down at an airport.
Unlike the device used in the failed Christmas Day 2009 plot by AQAP to blow up an airliner en route to Detroit, this explosive could have been detonated in two ways, in case one failed, the unnamed official was quoted as saying.
The main charge was a high-grade military explosive that "undoubtedly would have brought down an aircraft," the official said.
ABC News had reported earlier that the latest plot by AQAP was thwarted by a spy who infiltrated the group and took the explosive to Saudi Arabia.
The CIA and other government agencies declined to comment on the reports when contacted by AFP.
Saudi intelligence likely played a pivotal role in disrupting the conspiracy, possibly providing the double agent, former US officials said.
FBI experts yesterday were analysing the seized explosive that officials said was an updated version of the "underwear bomb" used in the failed Christmas Day 2009 attack.
Although officials touted the disrupted plot as a success, they acknowledged AQAP remained determined to strike and its master bombmaker, Ibrahim Hassan Taleh Al-Asiri, was apparently hard at work seeking to circumvent airport security.