Secret documents that allegedly detail the surveillance of AT&T phone lines under the Bush administration's terrorist surveillance program can be used in a lawsuit against the telephone giant, a federal judge ruled Wednesday, but the records will remain sealed.

U.S. District Judge Vaughn Walker rejected a bid by AT&T Inc. to return the records that were given to the privacy advocate Electronic Frontier Foundation by a former AT&T technician. But Walker said the records would remain under seal until it can be determined whether they reveal trade secrets.

"The best course of action is to preserve the status quo," Walker said.

The hearing is the first in a lawsuit challenging the administration's secretive terrorist surveillance program.

The lawsuit, filed by EFF in U.S. District Court, accuses AT&T of illegally cooperating with the National Security Agency to make communications on the company's networks available to the spy agency without warrants.

"They are asking this court to suppress evidence of AT&T's criminal activity," EFF lawyer Maria Morris said in arguing that the records remain part of the case.

AT&T lawyer David Anderson, arguing the records should be returned to the company, said, "I thought it was unfortunate counsel chose to use the terms 'criminal activities' and 'crimes."'

The lawsuit is based largely on the former technician's documents, which the technician and EFF assert show that the NSA is capable of monitoring communications on AT&T's network after the NSA installed equipment in secret rooms at AT&T offices in San Francisco, Seattle, San Jose, Los Angeles and San Diego.

San Antonio-based AT&T claims the documents involve trade secrets, and it has "an obligation to assist law enforcement and other government agencies responsible for protecting the public welfare."

The Bush administration, meanwhile, urged Walker to dismiss the case, saying it threatens to divulge state secrets and jeopardize national security. The government argued in briefs that the courts cannot decide the constitutionality of the president's asserted wartime powers to eavesdrop on Americans without warrants.

USA Today reported last week that the NSA was secretly collecting the records of phone calls by millions of ordinary Americans to build a database of all calls within the country.

Two major telecoms — Verizon and BellSouth — have said they did not provide customer call data to the NSA, but USA Today stood by its story. AT&T has not denied involvement.

President Bush announced in December that the NSA has been conducting warrantless surveillance of calls and e-mails thought to involve al-Qaida terrorists following the Sept. 11, 2001 attacks.