US authorities say there are new concerns about foreign fighters who may be able to cross international borders into Europe or the US.
Authorities are considering new airport security measures due to increased concern Al Qaeda in the Arabian Peninsula, or AQAP, has found a new way to get around current airport screening.
Security officials say a vulnerability has been identified in airport security because of AQAP advances.
Officials don't see an imminent threat, but one official says "we are steadily tracking significant threats from AQAP."
The White House Press Secretary says the Department of Homeland Security is regularly reviewing our security procedures to adapt to new threats faced by our transportation system.
The big concern is this Man Ibrahim al Asiri, AQAPs master bombmaker expert, is designing bombs with no metal and undetectable explosives similar to the device worn by Umar Farouk Abdulmutallab, the 2009 Christmas Day underwear bomber, targeting a US airliner.
The top US military commander in Europe notes terrorists have been eyeballing western airports for months.
Another concern is whether one of the next targets of Al Qaeda's most dangerous wing could be a Middle East shopping mall full of westerners.
Analysts say the attack on Kenya's Westgate Mall got days of worldwide attention. That's exactly what Al Qaeda wants without worrying about getting into the US to attack a mall.