Known detention facilities such as prisons at Guantanamo Bay, Bagram Air Force Base and Abu Gharib are listed, but the report revealed facilities in Afghanistan, Iraq, Pakistan, Jordan, and aboard US ships.

The centres failed to meet obligations under US and international law on the treatment of prisoners, said the report, 'Ending Secret Detention'. 'The abuses at Guantanamo Bay and Abu Gharib cannot be addressed in isolation,' said Deborah Pearlstein, director of Human Rights First's US Law & Security Program. 'The US government is holding prisoners in a secret system of off-shore prisons beyond the reach of adequate supervision, accountability, or law.'

Human Rights First is calling for a comprehensive response by Washington to end secret detentions, notify the families of the detainees, investigate abuses, implement preventative measures, release the location of the detention facilities, and give the Red Cross immediate access to all detainees.

The revelation comes as a CIA contractor was charged with assaulting an Afghan detainee who later died of his injuries. David Passaro , a former US Army Ranger hired by the CIA to conduct interrogations, was responsible for the death of Abd al-Wali, who died in June 2003 after two days of beatings. It was the first case in which a civilian has been charged in relation to prisoner abuse in Iraq or Afghanistan.

Separately, the US army appointed on 17 June a senior general to oversee an inquiry into prisoner General Paul Kern will head the investigation into the role of military intelligence personnel in the abuse at Abu Gharib.

Meanwhile, it emerged the same day that the US military has been secretly holding a suspected terrorist in Iraq on the orders of Defence Secretary Donald Rumsfeld. The Iraqi man has been held since November 2003 without being listed on any roll and without a prisoner number, a violation of the Geneva Conventions on treatment of prisoners.