The lawsuit contends that AT&T collaborated with the National Security Agency (NSA) in a government program to wiretap and collect information on millions of Americans' private communications .

The surveillance effort, conducted without warrants, was revealed late last year by the New York Times and other media outlets. President Bush has conceded that he authorized the snooping, which began as early as 2001 and was overseen by the National Security Agency.

Massive Fishing Expedition

In what the EFF called "the largest 'fishing expedition' ever devised," the NSA used computers to data -mine the contents of Internet and telephone communications for suspicious names, numbers, and words, and to analyze e-mail and telephone traffic data indicating who might be linked to "suspicious activities, suspected terrorists, or other investigative targets."

The lawsuit also alleges that AT&T continues to assist the government in its secret surveillance of millions of Americans.

"AT&T broke federal privacy laws in cooperating with the government and providing unfettered access to a company database as well as their networks," said Rebecca Jeschke, an EFF spokesperson. "The company knows the law, and they ignored it."

Database Compromised

AT&T was singled out by the foundation on the basis of evidence revealed in the media and an investigation conducted by the EFF, said Jeschke. "There may well be other telecom operators who collaborated on illegal surveillance, but AT&T's role is noteworthy given the amount of data they have," she added.

Indeed, the EFF lawsuit notes that the company provided access to its 300-terabyte Daytona database of caller information. The AT&T database is among the world's largest.

The government domestic-spying program, repeatedly defended by Bush and his administration as a vital weapon in the war on terrorism, also faces legal challenges from the American Civil Liberties Union, which has sued the NSA; the Center for Constitutional Rights, which has sued Bush, the head of the NSA, and other federal officials; and the Electronic Privacy Information Center, which is suing the U.S. Justice Department.

Jeschke said the EFF suit was filed on behalf of a class that includes all AT&T customers since 2001. It seeks monetary damages for those millions of individuals. The defendant has 30 days to respond or file a motion to dismiss the case.

Focal Point

Information stored by telecoms, Internet search firms, and other companies lately has become a focal point for government probes.

Google has refused to comply with a Department of Justice subpoena to provide the records of the searches conducted by Web users, a decision applauded by the EFF and privacy advocates.

In this instance, the government wants to review search records to determine whether a law designed to protect minors from pornographic Web sites is effective. Yahoo, MSN, and AOL all complied with the government's request.