WASHINGTON (Reuters) - President Barack Obama shrugged off a request by seven former CIA chiefs to end a probe into allegations of prisoner abuse, saying in an interview released on Sunday that “nobody’s above the law.”

U.S. President Barack Obama speaks to staff during his visit to the CIA headquarters in Langley, Virginia, in this April 20, 2009 file photo. REUTERS/Jason Reed/Files

U.S. Attorney General Eric Holder last month named a prosecutor to examine whether criminal charges should be filed filed against Central Intelligence Agency interrogators or contractors for going beyond approved interrogation methods.

A letter by the former CIA directors sent to Obama on Friday said the Justice Department’s investigation would hamper operations and damage the willingness of intelligence officers to take risks to protect the country.

“I appreciate the former CIA directors wanting to look after an institution that they helped to build,” Obama said in an interview with the CBS television show “Face the Nation.”

“But I continue to believe that nobody’s above the law. And I want to make sure that, as president of the United States, that I’m not asserting in some way that my decisions overrule the decisions of prosecutors who are there to uphold the law,” he said.

In a separate interview on CNN, Obama said, “I don’t want to start getting into the business of squelching, you know, investigations that are being conducted.”

Obama noted he consistently has said he wanted to look forward, not backward, on problems that occurred under the Bush administration involving the use of harsh interrogation methods like waterboarding and sleep and food deprivation.

Bush-era officials, including former Vice President Dick Cheney, have defended their actions and said the interrogations yielded valuable intelligence.

Civil liberties groups have accused the Bush administration of using torture to coerce information from terrorism suspects in violation of U.S. and international law.

Obama said on CBS that Holder has to make a judgment about what happened.

“My understanding is it’s not a criminal investigation at this point. They are simply investigating what took place,” he said. “I don’t want witch hunts taking place. I’ve also said, though, that the attorney general has a job to uphold the law.”

The letter to Obama was signed by three CIA directors under President George W. Bush -- Michael Hayden, Porter Goss and George Tenet -- as well as by John Deutch, James Woolsey, William Webster and James Schlesinger, who dates to the Nixon administration.

The interviews were taped on Friday. (Additional reporting by Jeremy Pelofsky; Editing by Doina Chiacu)