Former US State Department Counselor Philip Zelikow
In an interview with The Guardian, Zelikow said that he regards what officials called "enhanced interrogation," such as sleep deprivation and waterboarding, as torture.
"I do regard the interrogation practices and conditions of confinement, taken together, as torture -- in the ordinary layman's use of this term," he said.
Zelikow also noted that he had warned in a secret memo in 2006 that the torture techniques breached international and US war crimes laws.
The Bush administration immediately rejected Zelikow's report and ordered copies of the memo to be destroyed.
Zelikow explained that he has little doubt that the methods were unacceptable, saying "I think what they did was wrong."
He added that a later supreme court ruling that the Geneva Conventions do apply to those deemed by the Bush administration to be "illegal combatants" reinforced his position that some of the CIA's interrogation methods were illegal.
"If I was right, officials would be violating the federal War Crimes Act, a felony punishable by up to life imprisonment," he said.