The European Commission (search) said Thursday it will investigate reports that the CIA (search) set up secret jails in eastern Europe. The governments of the European Union's 25 members nations will be informally questioned about the allegations, EU spokesman Friso Roscam Abbing said.

"We have to find out what is exactly happening. We have all heard about this, then we have to see if it is confirmed."

He said such prisons could violate EU human rights laws and other European human rights conventions, and as the watchdog to ensure EU rules are properly adhered to the Commission would look into the issue. He cautioned that the EU head office as such could not take action against member states if they violated human rights.

"As far as the treatment of prisoners is concerned ... it is clear that all 25 member states having signed up to European Convention on Human Rights, and to the International Convention Against Torture, are due to respect and fully implement the obligations deriving from those treaties," Roscam Abbing told reporters.

U.S. officials refused to confirm or deny a report by the Washington Post that the CIA has been hiding and interrogating top Al Qaeda (search) suspects at a Soviet-era compound in several eastern European countries, some of which are EU member states.

According to the report, a covert prison system was set up by the CIA nearly four years ago which at various times included sites in eight countries, including Afghanistan and several eastern Europe nations. It quoted current and former intelligence officials and diplomats as sources for its story.