Former US Vice-President Dick Cheney has said the CIA should release documents showing the ‘success’ of waterboarding.

The widely condemned harsh-interrogation program was launched by former President George W Bush after the 11 September 2001 attacks.

In a Fox News interview, Mr Cheney said that he found it disturbing that President Obama did not also release memos that Mr Cheney said documented the effectiveness of the interrogations, a point contested by some experts.

The CIA declined to comment on Mr Cheney's remarks.

Mr Cheney’s comments come as US President Barack Obama visited CIA headquarters and emphasised the ongoing threat from al-Qaeda.

He said: ‘We live in dangerous times. I am going to need you more than ever’. He urged the employees not to be discouraged by public discussion of ‘mistakes’.

The visit represented a swift bid by Mr Obama to shore up CIA morale after he released last week classified Bush-era legal memos detailing the interrogation program.

His arrival, however, was met by enthusiastic cheers from the audience of about 1,000 CIA staff.

CIA Director Leon Panetta told President Obama he had the CIA's support and loyalty.

The interrogation program included waterboarding, a form of simulated drowning, widely considered torture. It came to symbolise US excesses in fighting terrorism after the 11 September attacks.

One memo said waterboarding had been used a total of 266 times on two of the three al-Qaeda suspects the CIA acknowledges were waterboarded.

Mr Obama said the memos were released because they had become the subject of a burdensome court fight and their covert nature had already been compromised.

Mr Panetta vowed to respect a ban on harsh interrogations that President Obama issued in January. He had opposed releasing the memos, joining former CIA directors concerned that their release could expose agents to retribution.