WASHINGTON (AP) -- The U.S. government will try to determine whether commercial data can be used to detect terrorist ''sleeper cells'' when it checks airline passengers against watch lists, the official running the project says.

The Transportation Security Administration has been testing the project, known as Secure Flight, since November, but it is being criticized on grounds it violates privacy laws.

Secure Flight is supposed to be a more accurate method of checking passenger manifests against terrorist watch lists than the current system, which is run by the airlines.

Many people who aren't terrorists - among them Sen. Edward M. Kennedy, a Democrat from Massachusetts - have been told they can't board flights because their names are similar to those on the no-fly list.

Secure Flight hit a snag Friday when congressional investigators said TSA had violated privacy protections when its contractor secretly collected 100 million records of commercially brokered information on at least 250,000 people.

Justin Oberman, in charge of Secure Flight at TSA, said the agency intends to do more testing of commercial data to see if it will help identify known or suspected terrorists not on the watch lists.

''We are trying to use commercial data to verify the identities of people who fly because we are not going to rely on the watch list,'' he said. ''If we just rise and fall on the watch list, it's not adequate.''