Airports were told Wednesday that more passengers should be randomly screened for explosives before, during and after they go through metal detectors, the official said. The screening could include swabbing travelers' hands or their carry-on luggage to check for traces of explosives, said the official, who requested anonymity to speak about security plans.
The heightened screening follows a Christmas Day attack on a Detroit-bound airliner. A Nigerian man accused of being trained by al-Qaida operatives has been charged with trying to blow up the plane with explosives hidden in his underwear.
Other security measures have been enhanced since the December attack. Heightened screening measures have been tested at five airports over the past month.
TSA spokeswoman Kristin Lee said the stepped-up screening is random and that travelers will not see the same procedures at all airports.