U.S. President Barack Obama, speaking in Washington on Tuesday, said the United States lost its 'moral bearings' with use of harsh interrogation methods on terrorism suspects. (Larry Downing/Reuters)

U.S. President Barack Obama acknowledged Tuesday that officials in the administration of his predecessor, George W. Bush, could potentially face prosecution for writing legal memos authorizing the CIA to use harsh interrogation methods on terrorism suspects.

Speaking for the first time since ordering the release of the secret legal briefs last week, Obama said the United States lost its "moral bearings" with use of the controversial tactics, which have been widely condemned by human rights groups and legal observers as torture.

With the release of the memos, the president ruled out prosecuting CIA officials who performed the harsh interrogations, provided they followed the guidelines set by government superiors who held that such practices were legal at the time.

But Obama said Tuesday it would fall to Attorney General Eric Holder to decide whether to prosecute lawyers who wrote the advice.

"There are a host of very complicated issues involved," Obama said.

Obama also said he could support a congressional investigation into the Bush-era terrorist detainee program, but only under certain conditions, such as if it were done on a bipartisan basis.

The four memos, long held secret by the Bush administration, revealed how its lawyers approved in extensive and often graphic detail the interrogation methods used against 28 terror suspects.

The rough tactics range from waterboarding — a form of simulated drowning — to using a plastic neck collar to slam detainees into walls.

The CIA has acknowledged using waterboarding on three high-level terror detainees in 2002 and 2003, with the permission of the White House and the Justice Department.

Obama released the memos despite the objections of some in the intelligence community, including former directors of the CIA. Current CIA director Leon Panetta had pressed for heavier censorship when they were released, but the memos were put out with only light redactions.

In an interview with Fox News Channel, former vice-president Dick Cheney defended his administration's actions, saying the government gained valuable intelligence from its aggressive interrogations.

"I know specifically of reports that I read, that I saw, that lay out what we learned through the interrogation process and what the consequences were for the country," Cheney said.

"I've now formally asked the CIA to take steps to declassify those memos so we can lay them out there and the American people have a chance to see what we obtained and what we learned and how good the intelligence was."

With files from The Associated Press