The device was found and seized in Yemen, with an attack set to commemorate the first anniversary of Osama Bin Laden’s death. However the CIA claims that there was never any threat to the public as a target had not been chosen by the terrorists. The device is now being studied by the FBI.

It is supposedly similar in design to the bomb strapped to the underwear of a Nigerian man, who attempted to explode a plane over Detroit on Christmas Day 2009, and was seized in the last ten days.

US officials told Reuters: "As a result of close co-operation with our security and intelligence partners overseas, an improvised explosive device (IED) designed to carry out a terrorist attack has been seized abroad.

"Initial exploitation indicates that the device is very similar to IEDs that have been used previously by al-Qaeda in the Arabian Peninsula (AQAP) in attempted terrorist attacks, including against aircraft and for targeted assassinations.”

US President Barack Obama was informed of the bomb plot back in April, and CIA officials in Yemen had been tracking the bomb building carefully ever since.

It is not clear who built the bomb, but reports suggests this would have been far more effective than the earlier model, with a better trigger mechanism, and it remains unclear whether it would have been picked up by airport security.