A report in Wednesday's Washington Post newspaper says the CIA has been holding and interrogating some of its most important al Qaida terror suspects at a secret Soviet-era compound in Eastern Europe.

The Post says the facility is part of a secret detention system set up by the intelligence agency in the aftermath of September 11, 2001 terrorist attacks. It says the facilities, referred to as "black sites" in classified government documents, have also been located in such countries as Thailand and Afghanistan.

The newspaper says it learned of the secret prison system from U.S. and foreign officials familiar with the arrangements. The CIA routinely refuses to comment on such issues.