In another episode, a gunshot was fired in a room next to a detainee to make the prisoner believe another suspect had been killed, according to the report, which a federal judge has ordered to be made public Monday in response to a Freedom of Information Act lawsuit filed by the American Civil Liberties Union.
The IG report's findings were first reported by Newsweek on its Web site.
Nashiri was one of three CIA prisoners subjected to water boarding, a brutal interrogation technique that simulates drowning that was among 10 techniques approved by the Bush administration's Justice Department in 2002. President Barack Obama and Attorney General Eric Holder have denounced water boarding as torture.
"The CIA in no way endorsed behavior- no matter how infrequent- that went beyond formal guidance," said agency spokesman Paul Gimigliano. He declined to comment on the contents of the IG report.
Holder is considering whether to appoint a criminal prosecutor to investigate the Bush administration's interrogation practices, a controversial move that would run counter to President Barack Obama's wishes to leave the issue in the past.
Gimigliano said the career prosecutors at the Justice Department have reviewed the report to determine if any laws were broken and whether the interrogators should be prosecuted.
"Professionals in the Department of Justice decided if and when to pursue prosecution," he said. "That's how the system was supposed to work, and that's how it did work."
Just one CIA contract interrogator, David Passaro, has been prosecuted. He was found guilty in 2007 in the beating death of a prisoner in Afghanistan.
