US and Yemeni officials said the supposed would-be bomber at the heart of an al-Qaeda airliner plot was actually an informant working for the CIA.
They said the informant was working for the CIA and Saudi Arabian intelligence when he was given the bomb. He then turned the device over to the authorities.
The officials, who spoke to US media on condition of anonymity on Tuesday, said the informant is safely out of Yemen.
Al Jazeera's John Terrett, reporting from Washington, said there has been “very limited comment on this story throughout the day from the [Obama] administration”.
Security procedures at US airports remained unchanged on Tuesday, a reflection of both the US confidence in its security systems and recognition that the government cannot realistically expect travellers to endure much more. Increased costs and delays to airlines and shipping companies could have a global economic impact, too.
"I would not expect any real changes for the traveling public," said House Intelligence Committee Chairman Mike Rogers. "There is a concern that overseas security doesn't match ours. That's an ongoing challenge."
The FBI is still analysing the explosive, which was intended to be concealed in a passenger's underwear. Officials said it was an upgrade over the bomb that failed to detonate on board an airplane over Detroit on Christmas 2009.
This new bomb contained no metal and used a chemical - lead azide - that was to be a detonator in a nearly successful 2010 plot to attack cargo planes.
Al Jazeera