WASHINGTON, Aug. 27 (Xinhua) -- The Central Intelligence Agency used severe sleep deprivation tactics on a detainee in late 2007, one year after the former Bush administration publicly banned its harshest interrogation methods, says a newly released internal CIA report.

    The report, disclosed by U.S. news outlets on Thursday, indicated that in 2007 Mohammed Rahim al-Afghani, a senior aide toAl Qaida leader Osama bin Laden, was kept awake for six days and was chained to the walls and floor of a cell.

    According to the report, the Bush administration publicly banned torture in 2006, but the CIA continued to use harsh interrogation tactics and torture to "break" the minds of detainees with permission from government lawyers.

    U.S. President Barack Obama reaffirmed a ban on torture soon after he took office in January and has ordered an investigation into the issue.

    On Monday, Attorney General Eric Holder named a special prosecutor to probe the CIA's use of torture.