Updated: 6:16 p.m.

Leading Congressional Democrats on Thursday dove back into the debate over the nation’s domestic wiretapping program in the wake of allegations that the National Security Agency overstepped its authority to conduct surveillance of American citizens, including at least one Member of Congress.

Lawmakers on Thursday announced their intention to review allegations that NSA’s surveillance activities have gone beyond what Congress intended — to intercept citizens’ phone calls, e-mails and other communications. The allegations also include charges that in at least one instance the NSA attempted to wiretap a phone call of an unidentified Member of Congress who was traveling abroad.

Speaker Nancy Pelosi (D-Calif.) said the matter would be investigated by Congress.

“These are disturbing allegations that deserve and are receiving the fullest attention of the appropriate committees of Congress. Congress expects to receive reports from the Inspectors General of key agencies regarding warrantless wiretapping activities, including those conducted under President Bush’s Terrorist Surveillance Program. Should these reports or any further investigations by Congress prove these allegations true, those who directed these activities in the Bush Administration must be held accountable,— Pelosi said in a statement.

House Judiciary Chairman John Conyers (D-Mich.) and subcommittee chairmen Jerrold Nadler (D-N.Y.) and Bobby Scott (D-Va.) issued a statement saying they were “alarmed— by the reports and called for a “full and prompt briefing of our Members.—

“While we appreciate that the processes set forth in last year’s FISA Improvements Act permit these potential abuses to be identified and disclosed, the program’s potential impingement of the rights of U.S. citizens remains a concern. We commend the Obama Administration for acting promptly, and hope we can work together to redouble efforts to protect these rights.—

House Intelligence Chairman Silvestre Reyes (D-Texas) issued a statement saying that his committee had already been “aggressively looking into the matter— after it was informed of problems at the NSA.

“To date, the Committee has held four separate oversight sessions, and I guarantee that the Committee will continue its inquiry and will be actively involved in monitoring this issue,— Reyes said.

Likewise, Senate Intelligence Chairman Sen. Dianne Feinstein (D-Calif.) announced that her committee would also hold hearings on the matter.

“These are serious allegations, and we will make sure we get the facts,— Feinstein said. “The Committee is looking into this, and we will hold a hearing on this subject within one month.—

According to a Wednesday report in the New York Times, the NSA attempted to conduct a wiretap on an unidentified lawmaker’s telephone conversations without a court order during a trip to the Middle East in 2005 or 2006. The NSA claimed the Member may have been in contact with “an extremist who had possible terrorist ties and was already under surveillance,— according to the newspaper.

Although the plan to conduct surveillance on the lawmaker was ultimately dropped, the allegations highlight the controversy of the Bush administration’s wiretapping program.

The revelation of the attempted wiretapping of a lawmaker brought quick condemnations from privacy advocates as well as calls for changes to the nation’s domestic and international spying laws.

Sen. Russ Feingold (D-Wis.), a member of the Intelligence Committee and a leading supporter of privacy rights, called for swift action to roll back provisions of federal wiretapping laws and called on the Obama administration to declassify documents detailing how the laws have been implemented.

“Congress must get to work fixing these laws that have eroded the privacy and civil liberties of law-abiding citizens. In addition, the administration should declassify certain aspects of how these authorities have been used so that the American people can better understand their scope and impact,— Feingold said.

By day’s end, the calls for investigations into the allegations were mounting, particularly among Democrats.

“These are very troubling allegations that need to be reviewed,— said Jim Manley, spokesman for Senate Majority Leader Sen. Harry Reid (D-Nev.).

House Majority Leader Steny Hoyer (D-Md.), who helped broker last year’s bipartisan deal on electronic spying legislation, said he is “deeply concerned— to learn of the NSA compliance failures.

“I understand that relevant Congressional committees were notified and have been conducting vigorous oversight on wrongdoings. I intend to look into this personally and ensure that all appropriate actions are being taken,— Hoyer said.

He was one of at least 56 current and former lawmakers who visited the Middle East in 2005 or 2006 when the effort to wiretap the unknown Member reportedly took place, according to OpenSecrets.org’s preliminary review of records related to privately funded travel

The current and former Members of the House who took privately funded trips to the Middle East during that time include: Hoyer, Lynn Woolsey (D-Calif.), Henry Waxman (D-Calif.), Chris Van Hollen (D-Md.), John Shimkus (R-Ill.), Christopher Shays (R-Conn.), John Salazar (D-Colo.), Tim Ryan (D-Ohio), Paul Ryan (D-Wis.), Dutch Ruppersberger (D-Md.), Tom Price (R-Ga.), Jerrold Nadler (D-N.Y.), Mike Michaud (D-Maine), Gregory Meeks (D-N.Y.), Jim McDermott (D-Wash.), Kenny Marchant (R-Texas), Dan Lungren (R-Calif.), John Carter (R-Texas), Russ Carnahan (D-Mo.), Jim Langevin (D-R.I.), John Kuhl (R-N.Y.), Dennis Kucinich (D-Ohio), Sam Johnson (R-Texas), Bobby Jindal (R-La.), Sheila Jackson Lee (D-Texas), Jesse Jackson Jr. (D-Ill.), Steve Israel (D-N.Y.), Virginia Foxx (R-N.C.), Eni Faleomavaega (D-American Samoa), Thelma Drake (R-Va.), John Doolittle (R-Calif.), Diana DeGette (D-Colo.), Jim Costa (D-Calif.), Eric Cantor (R-Va.), Ginny Brown-Waite (R-Fla.), Jo Bonner (R-Ala.), Henry Bonilla (R-Texas), Roy Blunt (R-Mo.), Earl Blumenauer (D-Ore.), Rob Bishop (R-Utah), Judy Biggert (R-Ill.), Shelley Berkley (D-Nev.), John Barrow (D-Ga.), Tammy Baldwin (D-Wis.) and Gary Ackerman (D-N.Y.).

Current and former Senators to visit the region during 2005 and 2006 include Ted Stevens (R-Alaska), Paul Sarbanes (D-Md.), Bob Menendez (D-N.J.), Dick Lugar (R-Ind.), Bob Bennett (R-Utah), Lamar Alexander (R-Texas), Byron Dorgan (D-N.D.), Tim Johnson (D-S.D.) and Hillary Rodham Clinton (D-N.Y.).

While the bulk of those Members traveled to Israel, several, including Blumenauer, Bennett, Baldwin, Stevens and Meeks, made visits to Jordan, Turkey, Qatar and other countries.

Additionally, a handful of lawmakers made visits to countries considered to be hostile to the U.S., including a trip to Syria by Kucinich in 2006. Several also visited the Gaza Strip and other territories currently occupied by Israel.

Steven T. Dennis and Jennifer Bendery contributed to this report.