Oct. 15 (Bloomberg) -- Three of the largest U.S. telephone companies declined to answer lawmakers' questions about Bush administration efforts to spy on Americans' phone calls and e- mails, saying the government forbade them from doing so.

``Our company essentially finds itself caught in the middle of an oversight dispute between the Congress and the executive relating to government surveillance activities,'' AT&T Inc. General Counsel Wayne Watts said in a letter to the House Energy and Commerce Committee that was released today by the panel.

Verizon Communications Inc., the second largest U.S. phone company after AT&T, and Qwest Communications International Inc., the fourth largest, also declined to answer many of the committee's questions.

Among the questions, posed by the committee on Oct. 2, were what information the carriers gave the administration without a court warrant, whether they were paid for any of it and whether the administration asked them to install equipment to intercept e-mails.

John Dingell, a Michigan Democrat who heads the Energy and Commerce Committee, and other Democrats called on the administration to answer questions about the spying.

``The water is as murky as ever on this issue, and it's past time for the administration to come clean,'' Representative Ed Markey, a Massachusetts Democrat who leads the panel's telecommunications subcommittee, said in a statement.

State Secrets

Verizon and Qwest said the Justice Department prohibited them from offering any substantive comment on their roles in the spy program. AT&T said Director of National Intelligence Michael McConnell invoked the state-secrets privilege to prevent the carrier from commenting.

McConnell's spokesman, Ross Feinstein, said in an interview today that the House and Senate Intelligence committees have the authority to oversee intelligence activities under the 1947 National Security Act.

White House spokesman Scott Stanzel declined immediate comment. Justice Department spokesman Dean Boyd declined to comment.

Verizon did answer a question from lawmakers about whether the administration asked it to provide ``communities of interest,'' the network of people with whom particular phone customers were in contact. The New York Times reported last month that the FBI had sought details on these networks.

`Calling Circle'

Verizon said the administration asked it to identify a `calling circle' for some telephone numbers. The carrier told the committee: ``Because Verizon does not maintain such `calling circle' records, we have not provided this information in response to these requests.''

Congress approved a temporary measure in July allowing spy agencies to continue intercepting, without a court warrant, phone calls and e-mails of foreign-based terrorists that are routed through the U.S. Lawmakers currently are working on new surveillance legislation.

McConnell acknowledged the existence of the program in August and said telecommunications companies should be given immunity from lawsuits claiming privacy violations. AT&T, Verizon and other carriers are being sued for providing customer information to the government.

Senator Dick Durbin of Illinois, the Democrats' No. 2 Senate leader, said last week he will resist the administration's demand for immunity for the carriers.

To contact the reporter on this story: Neil Roland in Washington at nroland@bloomberg.net.

Last Updated: October 15, 2007 18:55 EDT