The United States has announced new security measures to replace the mandatory screening of air travellers from 14 countries, imposed after the failed attack on a flight in December.
The measures are designed to significantly reduce the number of passengers pulled aside for additional screening and will not be based on nationality or passport, but on characteristics pulled together by intelligence agencies.
The new screening strategy, announced on Friday, results from a review ordered by Barack Obama, the US president.
Janet Napolitano, the department of homeland security secretary, said the new measures would "utilise real-time, threat-based intelligence along with multiple, random layers of security, both seen and unseen, to more effectively mitigate evolving terrorist threats".
Travellers will be picked out according to how closely they match intelligence on potential terrorist threats.
A senior administration official, who spoke to reporters on condition of anonymity, said the new system would require travellers who match information about terrorism suspects, such as a physical description, partial name or travel pattern, to undergo additional screening.
"So it's much more tailored to what the intel is telling us, what the threat is telling us, as opposed to stopping all individuals of a particular nationality or all individuals using a particular passport," the official said.
He described the measures being scrapped as a "blunt-force instrument".
The names of terrorism suspects identified by the US government will continue to be included on security watch lists and no-fly lists as a part of airline security.
The new policy affects US citizens, as well as travellers coming into the United States from abroad.
The measures in force since January required that passengers travelling to the US from 14 countries be subjected to especially rigorous pre-flight screening.
The US government implemented those security measures after a Nigerian man tried to detonate explosives hidden in his underwear on a flight to Detroit from Amsterdam on December 25, 2009.
Questions have been raised about why Umar Farouk Abdulmutallab, who was charged with trying to blow up the airliner, was not stopped before he got on the flight.
The 14 countries were those on the US list of "state sponsors of terrorism" - Cuba, Iran, Sudan and Syria - as well as Afghanistan, Algeria, Iraq, Lebanon, Libya, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen.
|The new measures will apply to US citizens, as well as foreigners travelling to America [AFP]
Saudi Arabia, Algeria and Nigeria - US partners in the fight against al-Qaeda - were angered at being included on the list.
Under the new measures, if there was information about an individual of interest coming from a particular Asian country who recently travelled to certain countries in the Middle East and was of a certain nationality and age range, that data would be compared with travellers to the United States at foreign airports.
Anyone who fits the data could be subjected to additional screening procedures and pulled aside for questioning by airline or airport security officials.
US officials have been consulting with countries and foreign carriers with direct flights to the United States about airline security, the administration official said.
"It is designed to be much more tailored so that we don't stop everybody coming from a certain country, because that information is out, and if I'm a terrorist, the last thing I want to do then is send somebody with this passport, going that way," the official said.