A former director of the Central Intelligence Agency (CIA) has called Dick Cheney a "vice president for torture."
Admiral Stansfield Turner, who was in charge of the CIA during the 1970s, said Mr Cheney was overseeing torture policies of possible terrorist suspects and was damaging America's reputation by doing so.
Speaking on ITV news Mr Turner said: "We have crossed the line into dangerous territory. I am embarrassed that the USA has a vice president for torture. I think it is just reprehensible."
He added: "He [Mr Cheney] advocates torture, what else is it? I just don't understand how a man in that position can take such a stance."
President Bush and other leading members of the his administration have consistently denied that detainees suspected of belonging to al-Qaeda were tortured for information.
But his opponents and human rights campaigners have claimed that many men taken captive in Iraq and Afghanistan have been subjected to torture to extract information.
Republican Senator John McCain has passed a provision to a defence Bill in the Senate banning "cruel, inhuman or degrading treatment" of all US detainees.
But the White House has apparently threatened to veto the measure if it is passed by the House of Representatives.