The US has admitted for the first time that it has not given the Red Cross access to all detainees in its custody.
The state department’s top legal adviser, John Bellinger, made the admission but gave no details about where such prisoners were held.
Correspondents say the revelation is likely to increase suspicion that the CIA has been operating secret prisons outside international oversight.
Video report at streaming at the BBC
In past visits to detainees in Iraq the Red Cross confirmed treatment “tantamount to torture,” and authorities were pressed to admit that 70 to 90 percent of Iraqi detainees had been arrested by mistake.