CIA foils Al Qaeda pants bomb plot to mark anniversary of Bin Laden's death

American officials said the device was similar to the one that failed to detonate on a Detroit-bound plane on Christmas Day in 2009, but that it was far more sophisticated.

The plot is believed to have originated in Yemen.

The FBI recovered the explosive but did not confirm whether the terrorist responsible for using it was captured or killed.

Technicians are now analysing the bomb and suspect it may have been created by al-Qaeda's "master" bomb maker, Ibrahim al-Asiri.

Al-Asiri recruited his brother, Abdullah, as a suicide bomber to blow up the chief of security Mohammed bin Nayef, in Jeddah, Saudi Arabia in 2009. Abdullah detonated a bomb planted in his rectum, but Bin Nayef survived.

The Saudi is understood to have made the bomb worn by Umar Farouk Abdulmutallab in his unsuccessful attempt to destroy a Northwest Airlines flight on Christmas 2009.

Al-Asiri is also thought to have been behind two bombs planted in print cartridges and put on US cargo planes in 2010.

Both explosives were discovered and safely removed at East Midlands Airport in Leicestershire.

The latest bomb did not contain any metal elements and is likely to have passed unnoticed through a standard airport metal detector.

However, newer body scanners common at American airports may have detected it.