Barack Obama said he could support a congressional investigation
US President Barack Obama has left open the possibility of prosecuting officials who wrote CIA memos allowing harsh interrogation techniques.
It would be up to the attorney general whether to prosecute, Mr Obama said.
The memos detailed a range of methods the CIA could use on terrorism suspects under the Bush administration.
Mr Obama had said he would not use anti-torture laws to prosecute CIA personnel who relied in good faith on legal opinions issued after 9/11.
The BBC's James Coomarasamy in Washington says the president's comments marked a change of tone amid growing pressure from the Democratic Party not to rule out potential prosecutions.
"With respect to those who formulated those legal decisions, I would say that that is going to be more of a decision for the attorney general within the parameters of various laws," Mr Obama said.
He also said he could support a congressional investigation of the issue if it was conducted in a bipartisan way.
White House chief of staff Rahm Emanuel had previously said in a television interview that the administration did not want to pursue those who "devised policy".
The memos revealed that two al-Qaeda suspects were subjected to waterboarding - a technique which simulates drowning - 266 times.
Other methods mentioned in the memos include week-long sleep deprivation, forced nudity and the use of painful positions.
Former Vice-President Dick Cheney has said the techniques produced results.
He has called for the release of additional documents that he said would show what the techniques yielded.
On Thursday, when the memos were released, Mr Obama said CIA personnel working from Bush administration legal opinions would not be prosecuted.
His comments drew criticism from human rights organisations and UN officials, who say charges are necessary to prevent future abuses and in order to hold people accountable.
Speaking to reporters on Tuesday, Mr Obama said the episode involved a "host of very complicated issues".
An investigation would be acceptable, he said, "outside of the typical hearing process" and with "independent participants who are above reproach".
He added: "As a general view, I do think we should be looking forward, not back.
"I do worry about this getting so politicised that we cannot function effectively and it hampers our ability to carry out critical national security operations."