American interrogators at the notorious Guantanamo Bay prison facility were using techniques inspired by the ones used by Chinese during the Korean war to get confessions from US prisoners, a media report said on Wednesday.

The military trainers who came to Guantanamo Bay in December 2002 based an entire interrogation class on a chart showing the effects of "coercive management techniques" for possible use on prisoners, including "sleep deprivation," "prolonged constraint," and "exposure," the New York Times said.

All these methods were once described by the Americans as torture.

What the trainers did not say, and may not have known, was that their chart had been copied verbatim from a 1957 Air Force study of Chinese Communist techniques used during the Korean War to obtain confessions, many of them false, from American prisoners.

The recycled chart is the latest and most vivid evidence of the way Communist interrogation methods that the US long described as torture became the basis for interrogations both by the military at the base at GuantanamoBay, Cuba, and by the Central Intelligence Agency, it said.

Some methods, the paper said, were used against a small number of prisoners at Guantanamo before 2005, when Congress banned the use of coercion by the military.

The CIA is still authorised by President Bush to use a number of secret "alternative" interrogation methods.

Several Guantanamo documents, including the chart outlining coercive methods, were made public at a Senate Armed Services Committee hearing June 17 that examined how such tactics came to be employed, it said.