Former US Vice-President Dick Cheney has said it is an "outrage" that the Obama administration continues to investigate CIA agents who interrogated terror suspects, claiming they did nothing.

Several Republicans and ex-officials have asked the Justice Department to drop the investigation, launched nearly two years ago by Attorney General Eric Holder.

"It's unfortunate. These men deserve to be decorated. They don't deserve to be prosecuted," Fox News quoted Cheney, as saying.

He said Holder's decision to reopen the case against CIA agents sets a "terrible precedent."

"These are government employees. They did nothing wrong, as best as any of us knows. It is an outrage that we would go after the people who deserve the credit for keeping us safe for seven and a half years," Cheney said.

Former Defense Secretary Donald Rumsfeld also said the Obama administration should set the CIA probe "aside" and move on, calling it a "most unfortunate thing."

"These people were operating at the direction of the president. They were doing things that had been approved by the Department of Justice," said Rumsfeld.