Sign up to The Irish Times Archive (1859 - 2008)My Account »

CIA interrogators used the waterboarding technique on Khalid Sheik Mohammed, the admitted planner of the September 11th attacks, 183 times and 83 times on another al-Qaeda suspect, the New York Timeshas reported.

The newspaper  said a 2005 Justice Department memorandum showed that Abu Zubaydah, the first prisoner questioned in the CIA's overseas detention program in August 2002, was waterboarded 83 times, although a former CIA officer had told news media he had been subjected to only 35 seconds underwater before talking.

President Barack Obama has banned the use of waterboarding, overturning a Bush administration policy that it did not constitute torture.

The Justice Department memo said the simulated drowning technique was used on Mohammed 183 times in March 2003. The Timessaid some copies of the memos appeared to have the number of waterboardings redacted while others did not.

The Senate Intelligence Committee is investigating the CIA interrogation program, which under Mr Bush also included slamming prisoners into walls, shackling them in uncomfortable positions and depriving them of sleep.

Bush administration officials had claimed such methods were needed to get information but the repeated use of the waterboard on Zubaydah and Mohammed were sure to raise questions about its effectiveness.