The government has modified the terrorist data base and the process as a result of which even a single trip to the US would add a suspect to this list which now numbers more than 440,000, a media report said on Thursday.
A year after a Nigerian man tried to blow up a plane over the US air skies, US officials have now "effectively in a broad stroke lowered the bar for inclusion," The Washington Post reported.
Timothy Healey, Director of FBI’s Terrorist Screening Centre, said the new guidelines balance the protection of Americans from terrorist threats with the preservation of civil liberties.
He was quoted as saying by the daily that the watch list today is "more accurate, more agile," providing valuable intelligence to a growing number of partners that include state and local police and foreign governments.
The government's master watch list is one of roughly a dozen lists, or databases, used by counter-terrorism officials, the daily said.
The master watch list is used to screen people seeking to obtain a visa, cross a US border, or board an airliner in or destined for the United States, the report said, adding the standard for inclusion on it remains the same as it was before - that a person is "reasonably suspected" to be engaged in terrorism-related activity.
"Despite the challenges we face, we have made significant improvements," Michael E Leiter, director of the National Counter-terrorism Center, was quoted as saying.
"And the result of that is, in my view, that the threat of that most severe, most complicated attack is significantly lower today than it was in 2001," he underlined.
Each day there are 50 to 75 instances in which a law enforcement official or government agent stops someone who a check confirms is on the watch list, a senior official at the Terrorist Screening Centre said.
Such "positive encounters" can take place at airports, land borders or consular offices, or during traffic stops, the daily reported.
The Terrorist Identities Datamart Environment (TIDE), according to the report, has now gone a multi-million upgrade.
According to its information officer, Vicki Jo McBee, the new system will also ease the sharing of fingerprints and iris and facial images of people on the watch list among screening agencies.
Rather than sending data once a night to the Terrorist Screening Center's watch list, which can take hours, the new system should be able to update the list almost instantly as names are entered, he said.