Fourteen Libyans, many of them members of an Islamist group who had worked to overthrow Libyan leader Moammar Gadhafi, were later turned over to Libya where they were further mistreated, Human Rights Watch says in a 154-page report.
"The scope of Bush administration abuse appears far broader than previously acknowledged and underscores the importance of opening up a full-scale inquiry into what happened," said Laura Pitter, a counter-terrorism adviser at Human Rights Watch who wrote the report.
Documents that Human Rights Watch found abandoned in the offices of Libyan intelligence after Tripoli fell to rebel forces also were used in the report.
The report says members of the Libyan Islamic Fighting Group living outside of Libya were arrested by the United States following the attacks of Sept. 11, 2001, and held without charge before being rendered to the Libyan government.
Five of the former group members told HRW they were mistreated at two U.S.-run detention facilities in Afghanistan.
Abuses they described included being chained to walls while naked or diapered for weeks or months, restrained in painful positions, beaten, denied baths for months and exposure to loud music.
One of the men said he was waterboarded.
The CIA has publicly acknowledged waterboarding only three people, The New York Times reported.
CIA spokeswoman Jennifer Youngblood, asked about the report of the alleged fourth case of waterboarding, said the agency was "on the record" as subjecting only three people to the treatment. She noted the Justice Department had reviewed the treatment of more than 100 detainees held by the agency and "declined prosecution in every case."