LOS ANGELES  —  A federal judge on Friday temporarily blocked a rule saying the government's new airport security screeners must be U.S. citizens.

The portion of the Aviation and Transportation Security Act barring non-citizens from the positions is unconstitutional, U.S. District Judge Robert Takasugi ruled.

Takasugi's preliminary injunction will remain in place until trial in a civil rights lawsuit brought by nine plaintiffs at Los Angeles and San Francisco International Airports. No date has been set.

The ruling will affect as many as 8,000 airport screeners, most of whom already have lost their jobs, said Ben Wizner, a lawyer for the American Civil Liberties Union of Southern California, which brought the case.

Plaintiffs lawyers said the ruling will apply to airports nationwide and allow the workers to reapply for jobs that became federal positions following the Sept. 11 terrorist attacks.

ACLU lawyers also said they hoped the judge's decision would convince Congress to pass an amendment before the Senate that would allow U.S. nationals to hold airport security screening jobs. One of the plaintiffs is from American Samoa, who had been barred from applying as a baggage screener.

U.S. Justice Department lawyer Elizabeth Shapiro declined to comment on the ruling. She said it was not clear that the injunction would apply nationwide.

Wizner, however, said he interpreted the ruling as applying to those workers already effected and any non-citizens who want to apply for a job.