WASHINGTON — House Democrats demanded Thursday that the Justice Department turn over two secret memos that reportedly authorize painful interrogation tactics against terror suspects — despite the Bush administration's insistence that it has not violated U.S. anti-torture laws.

Spokespeople for the White House and the Justice Department said a memo written in February 2005 on this subject did not change an administration policy issued in 2004 that publicly renounced torture as "abhorrent."

House Judiciary Chairman John Conyers and Rep. Jerrold Nadler, D-N.Y., promised a congressional inquiry into the two Justice Department legal opinions that reportedly "explicitly authorized the use of painful and psychological tactics on terrorism suspects."

"Both the alleged content of these opinions and the fact that they have been kept secret from Congress are extremely troubling, especially in light of the department's 2004 withdrawal of an earlier opinion similarly approving such methods," Conyers, D-Mich., and fellow House Judiciary member Nadler wrote in a letter Thursday to Acting Attorney General Peter D. Keisler.

The two Democrats also asked that Steven Bradbury, the Justice Department's acting chief of legal counsel, "be made available for prompt committee hearings."

The memos were disclosed in Thursday's editions of the The New York Times, which reported that the 2005 legal opinion authorized the use of simulated drownings and freezing temperatures while interrogating terror suspects, and was issued shortly after then-Attorney General Alberto Gonzales took over the Justice Department.

That secret opinion, which explicitly allowed using the painful methods in combination, came months after a 2004 opinion in which the Justice Department publicly declared torture "abhorrent" and the administration seemed to back away from claiming authority for such practices.

White House spokeswoman Dana Perino denied that the 2005 opinion cleared the way for the return of painful interrogation tactics or superseded U.S. anti-torture law. "This country does not torture," she told reporters. "It is a policy of the United States that we do not torture and we do not."

Perino did confirm existence of the Feb. 5, 2005, classified opinion, however. But she would not comment on whether it authorized specific practices, such as head-slapping and simulated drowning, and said the 2005 opinion did not reinterpret the law.

Additionally, Justice Department spokesman Brian Roehrkasse said the 2004 opinion remains in effect and that "neither Attorney General Gonzales nor anyone else within the department modified or withdrew that opinion."

"Accordingly, any advice that the department would have provided in this area would rely upon, and be fully consistent with, the legal standards articulated in the December 2004 memorandum," Roehrkasse said in a statement.

The dispute may come down to how the Bush administration defines torture, or whether it allowed U.S. interrogators to interpret anti-torture laws beyond legal limits. CIA spokesman George Little said the agency sought guidance from the Bush administration and Congress to make sure its program to detain and interrogate terror suspects followed U.S. law.

"The program, which has taken account of changes in U.S. law and policy, has produced vital information that has helped our country disrupt terrorist plots and save innocent lives," Little said in a statement. "The agency has always sought a clear legal framework, conducting the program in strict accord with U.S. law, and protecting the officers who go face-to-face with ruthless terrorists."

The issue quickly hit the presidential campaign trail.

"The secret authorization of brutal interrogations is an outrageous betrayal of our core values, and a grave danger to our security," Democratic presidential candidate Barack Obama said in a statement. "We must do whatever it takes to track down and capture or kill terrorists, but torture is not a part of the answer — it is a fundamental part of the problem with this administration's approach."

Perino said the 2004 anti-torture opinion was a "broad and general" interpretation of the law and "the February 2005 one was different in that it was focused on specifics." She defended the policies as necessary to protect the country.

"We know that these are ruthless individuals who will do anything, and that they're very patient; that they'll do anything to try to carry out their attacks," Perino told reporters. "And this president has put in place — all within the foursquare corners of the law — tools in the global war on terror that we need."

The February 2005 Justice opinion was followed later in 2005 by another one, just as Congress was working on an anti-torture bill, secretly declaring that none of the CIA's interrogation practices violated the new law's standard against "cruel, inhuman and degrading" treatment, The Times said. The newspaper cited interviews with unnamed current and former officials.

The 2005 opinions approved by Gonzales remain in effect despite efforts by Congress and the courts to limit interrogation practices used by the government in response to the Sept. 11, 2001, terrorist attacks. Gonzales resigned last month under withering criticism from congressional Democrats and a loss of support among members of his own party.

The authorizations came after the withdrawal of an earlier classified Justice opinion, issued in 2002, that had allowed certain aggressive interrogation practices so long as they stopped short of producing pain equivalent to experiencing organ failure or death. That controversial memo was withdrawn in June 2004.

After Gonzales took office, the new secret opinions were issued.

Associated Press reporters Deb Riechmann and Pamela Hess contributed to this report.