The FBI wants to interview top members of the House of Representatives and senators from both parties about the leak to The New York Times about the National Security Agency's domestic surveillance program, two sources with knowledge of the leak investigation confirmed to CNN.

The Capitol Hill newspaper Roll Call first reported that the FBI wanted to question members of Congress as part of its probe. The sources do not know if any members have actually been interviewed yet.

The FBI declined to comment.

The New York Times in December reported the existence of the program, which allows phone calls between the United States and overseas to be monitored without a court warrant so long as one party is a terror suspect.

Only a few members of the House and Senate were briefed on the NSA program before it became public.

One source with knowledge of the investigation said, "There is only a certain universe of people who had this information and could have leaked it. Obviously any investigation would focus on that universe. If members who had knowledge were not interviewed, then any investigation would not be complete."

The source added, "This is common sense."

A spokesman for the House Intelligence Committee would not say whether its chairman, Rep. Peter Hoekstra, R-Mich., had been asked for an interview but did say he has been questioned in the past on other investigations.

"It's his belief that you must vigorously pursue all illegal leaks to send a message that there is no tolerance," spokesman Jamal Ware told CNN.

A House Intelligence Committee official said there are discussions between congressional officials and the Justice Department and FBI about the interviews.

"The full scope of this is still being negotiated between all sides," the official said. "There are a broad range of issues to consider. There are constitutional separation of power issues that have to be resolved."

A spokesman for Rep. Jane Harman, D-Calif., ranking minority member on the House Intelligence Committee, said she has not been contacted about "any inquiry" regarding the NSA leak.

House Minority Leader Nancy Pelosi, D-Calif., who used to sit on the Intelligence Committee, told reporters, "It is not unusual ... that the investigation would include all of those who had access or had been briefed about the program. If asked, I will certainly participate in that inquiry."

Pelosi's spokeswoman, Jennifer Crider, told CNN Pelosi has not been notified that the FBI wants to interview her about the leak on the NSA story.

"I know for a fact she has not been notified in writing," Crider said.

A source with knowledge of the leak investigation said there should not be a separation of powers concern regarding interviews with members of Congress, saying that lawmakers have been talked to in previous leak inquiries.

FBI spokesman Richard Kolko said, contacted for reaction, said, "This is a sensitive and ongoing matter, and it would be inappropriate for the FBI to comment on this investigation at this time."