Updated at 9:44 p.m. ET -- Reversing its course, the White House will now brief members of Congress on the legal justifications for drone strikes against U.S. citizens, an administration official said Wednesday night.

"Today, as part of the president's ongoing commitment to consult with Congress on national security matters, the president directed the Department of Justice to provide the congressional intelligence committees access to classified Office of Legal Counsel advice related to the subject of the Department of Justice White Paper," the official said.

The Justice Department paper, first obtained by NBC News, concluded that the United States can legally order the killing of American citizens believed to be al-Qaida leaders.

Until Wednesday, the administration would not even confirm these memos existed.

Sen. Dianne Feinstein, chairman of the Senate Select Committee on Intelligence, said in a statement Wednesday night she was pleased with the White House's decision.

"I am pleased that the president has agreed to provide the Intelligence Committee with access to the OLC opinion regarding the use of lethal force in counterterrorism operations. It is critical for the committee's oversight function to fully understand the legal basis for all intelligence and counterterrorism operations," Feinstein's statement read.

Earlier Wednesday, the Associated Press reported that White House spokesman Jay Carney said Obama was engaged in an internal process deliberation to determine how to balance the nation's security needs with its values. He said Obama was committed to providing more information to Congress, even as he refused to acknowledge whether the drone memo even existed.

"He thinks that it is legitimate to ask questions about how we prosecute the war against al-Qaida," Carney said. "These are questions that will be with us long after he is president and long after the people who are in the seats that they're in now have left the scene."

Some legal experts warned that the secret memo threatened constitutional rights and dangerously expanded the definition of national self-defense and of what constitutes an imminent attack.

The administration’s decision to give the memo to the congressional intelligence committees comes a day before the Senate confirmation hearing Thursday for John Brennan, President Barack Obama’s pick to lead the CIA. Brennan was an architect of the administration’s controversial escalation of drone strikes to take out suspected militants.

Members of Congress have expressed serious reservations about the memo. On Wednesday, Rep. Ron Wyden, D-Ore. and a member of the House Intelligence Committee, told NBC News Radio that the memo “doesn’t answer the central questions” revolving around an important policy decision: "When does the government have the legal right to kill an American?"

"The administration has essentially been stonewalling the committee and myself and others for over two years by not actually making that memo available with someone willing to answer questions about it," Wyden said.

Related:

Wyden vows to 'pull out all the stops' to get 'actual legal analysis' on drones

White house drone memo: Four key questions