A global human rights watchdog says the United States operated a secret prison in Afghanistan as recently as last year where detainees were tortured.
The new directive is intended to prevent further abuse
US-based Human Rights Watch says it has credible reports that eight people now being held at Guantanamo Bay were tortured at the prison.
The organisation says the accusation is based on accounts given to its lawyers.
The US has been criticised by human rights groups over its treatment of detainees from Afghanistan and Iraq.
Human Rights Watch group says the detainees were kept in total darkness and mistreated.
"They were chained to walls, deprived of food and drinking water, and kept in total darkness with loud rap, heavy metal music, or other sounds blared for weeks a time," the organisation said.
"Some detainees said they were shackled in a manner that made it impossible to lie down or sleep, with restraints that caused their hands and wrists to swell up or bruise."
Human Rights Watch says the accounts warrant an official investigation.
The US has neither confirmed nor denied reports of secret CIA-run prisons in other countries, but says none of its interrogation techniques amounts to torture.
"I can say that we, in fact, are consistent with the commitments of the United States that we don't engage in torture and we don't," US Vice President Dick Cheney said in an interview on ABC News.
About 500 prisoners remain at Guantanamo, many of them captured in Afghanistan. Some have been held for nearly four years without charge.
United Nations officials have been trying to visit the camp since it opened in 2002 but have only been offered restricted access, which it has rejected.