The US has announced that it will begin profiling US-bound passengers to determine who should get extra screening.
The measures will replace mandatory enhanced screening of all travellers from 14 nations, brought in after the failed attack on a flight in December.
Travellers will be picked out according to how closely they match intelligence on potential terrorist threats.
The new strategy results from a review ordered by President Barack Obama.
Department of Homeland Security Secretary Janet Napolitano said the new measures would use “real-time, threat-based intelligence along with multiple, random layers of security, both seen and unseen, to more effectively mitigate evolving terrorist threats”.