The National Security Agency is not required to release details about its secret wiretapping program, a federal judge said Monday.

The People for the American Way Foundation, a liberal advocacy group, sued to obtain records under the Freedom of Information Act. The group sought to find out how many wiretaps were approved and who reviewed the program.

President Bush has acknowledged the existence of the program, which he calls the Terrorist Surveillance Program. The National Security Agency monitors phone calls and e-mails between people in the U.S. and people in other countries when a link to terrorism is suspected.

Civil liberties group criticize it as an expansion of presidential power, and a federal judge has said it is unconstitutional. The Justice Department says it is a necessary tool to fight terrorism.

The NSA denied the request for documents, saying the records would jeopardize national security. The advocacy group argued that the law can't be used to protect the government from disclosing details about illegal programs.

U.S. Judge Ellen Segal Huvelle disagreed, saying that even if the program is ultimately determined to be illegal, it doesn't change the fact that the materials are classified and are not covered by the Freedom of Information Act.