"The court is persuaded that requiring AT&T to confirm or deny whether it has disclosed large quantities of telephone records to the federal government could give adversaries of this country valuable insight into the government's intelligence activities," U.S. District Judge Matthew F. Kennelly said.

Kennelly ruled in a lawsuit filed by the American Civil Liberties Union of Illinois on behalf of author Studs Terkel and other activists who said their constitutional rights were violated because of a National Security Agency program of gathering phone company records.

Justice Department attorneys had argued it that would violate the law against divulging state secrets for AT&T to say whether it had provided telephone records to the supersecret spy agency.

The ACLU argued that the practice was no longer secret, because numerous news reports had made it clear that phone records had been given to the agency.

But the judge said the news reports amounted to speculation and in no way constituted official confirmation that phone records had been turned over.

He also said Terkel and the other plaintiffs in the lawsuit, which sought class-action status, had not shown that their own records had been provided to the government. As a result, they lacked standing to sue the government, he said.