ABC News has learned that intelligence officials know that al-Asiri has been busy training new terrorists to make similar undetectable devices.
People who don't show up on watch lists have been told to attack when and where they choose. Intelligence officials say al-Asiri is branching out because he fears being caught and neutralized.
The FBI is studying the explosive device recovered by a double agent posing as an al Qaeda terrorist. The bomb, believed to be designed by al-Asiri, was designed to slip inside form-fitting, brief-style underwear. Officials say it was a sophisticated upgrade from the bomb in the failed Christmas Day attack in 2009.
The new device contained no metal and utilized the chemical lead azide, which is known as a reliable detonator.
It is likely it could have passed through an airport metal detector, but security officials say bombs like it could have been detected by airport body scanners or security pat-downs.
The Associated Press contributed to this report.
