A U.S. newspaper says the U.S. Central Intelligence Agency has maintained a secret prison for valuable al-Qaida detainees at the U.S. detention center in Guantanamo Bay, Cuba.

The Washington Post Friday quotes military officials and intelligence officers as saying the existence of the prison has never been made public before.

The Post says it is unclear whether the facility is still in operation. But, it cites intelligence sources as saying the prison has housed detainees from Pakistan, West Africa, Yemen and other countries.

The newspaper says most international terrorism suspects in U.S. custody are held by the U.S. military - not the CIA. Those held by the military are guaranteed access to the International Committee of the Red Cross.

But the Post says the CIA detainees are held under separate rules and far greater secrecy.

Officials at the CIA had no immediate comment.