WASHINGTON ( CNN ) -- CIA interrogators used waterboarding at least 266 times on two top al Qaeda suspects , according to a Bush-era Justice Department memo released by the Obama administration . Khalid Sheikh Mohammed , seen in a December sketch , was waterboarded 183 times in a month , a memo says . The controversial technique that simulates drowning -- and which President Obama calls torture -- was used at least 83 times in August 2002 on suspected al Qaeda leader Abu Zubaydah , according to the memo . Interrogators also waterboarded Khalid Sheikh Mohammed 183 times in March 2003 . Mohammed is believed to be the mastermind behind the September 11 , 2001 , terrorist attacks on the United States . Obama released the memo Thursday , saying that `` exceptional circumstances surround these memos and require their release . '' Watch other tactics outlined in memos » . The memo , dated May 30 , 2005 , was from then-Deputy Assistant Attorney General Steven G. Bradbury to John Rizzo , who was acting general counsel for the CIA . It paints a different picture from the one described by former CIA officer John Kiriakou . In a December 2007 interview with CNN , Kiriakou said Zubaydah had been waterboarded for `` about 30 seconds , 35 seconds '' and agreed to cooperate with interrogators the following day . In an interview on `` Fox News Sunday , '' Michael Hayden , who directed the CIA from 2006 to 2009 , was asked about the number of times Mohammed was waterboarded . Hayden denounced the release of the memos and did not comment on the number , saying it was his understanding that the frequency of waterboarding was among the operational details that had not been declassified . Watch one expert say tactics 'worse than Abu Ghraib ' » . The 2005 memo refers to a letter that had contained the numbers as well . Part of the reference to the letter was redacted in the released memo . Waterboarding is among the interrogation tactics that Obama has prohibited through an executive order . The CIA also has admitted waterboarding Abd al-Rahim al-Nashiri , the first person charged in the United States for the 2000 attack on the USS Cole in Yemen that killed 17 U.S. sailors . Obama said last week he felt comfortable releasing the classified memos because the Bush administration acknowledged using some of the practices associated with the memos , and the interrogation techniques were widely reported and have since been banned . `` Withholding these memos would only serve to deny facts that have been in the public domain for some time , '' Obama said in a statement . `` This could contribute to an inaccurate accounting of the past , and fuel erroneous and inflammatory assumptions about actions taken by the United States . '' The president applauded the work of the U.S. intelligence community and said no one who `` carried out their duties relying in good faith upon legal advice from the Department of Justice '' would be prosecuted .
Memo : Khalid Sheikh Mohammed waterboarded 183 times in one month . Comment: Obama : Memos released because methods were reported , are now banned . CIA 's ex-chief denounces decision to release memos .