The US Senate has urged the country's intelligence chief to give it a report on allegations that the CIA ran secret overseas jails for terrorism suspects.
Guantanamo inmates could be denied the right to a legal challenge
John Negroponte should testify in secret to two Congressional intelligence panels, the Senate voted.
It follows a report, that has not been officially confirmed or denied, that the CIA had jails in Europe and Asia.
Senators also voted to bar detainees at Guantanamo Bay from taking legal action in US courts.
However, the provision would need to go through several more steps before becoming law.
If it does become law it will leave without effect a 2004 Supreme Court opinion that the Guantanamo inmates had a right to challenge their detentions.
'In the dark'
Senator John Kerry proposed the call for a report into the alleged secret jails.
"I don't have any doubt in the American public's determination to win the war on terror," the former presidential challenger said.
"But I do know that any administration that tries to keep Congress in the dark damages the cause for which we are all fighting."
According to the Washington Post newspaper, centres - known as "black sites" - were set up in the wake of the 11 September attacks on the US in 2001.
About 30 detainees, considered major terrorism suspects, were held by the CIA in the "black sites", the paper said.
Another group of at least 70 detainees have since been handed over to intelligence services in Egypt, Jordan, Morocco, Afghanistan and other countries.
The European Union has said it will examine reports that the CIA set up prisons in unnamed Eastern European states.
A rights group has suggested Romania and Poland might have been involved, but both states have issued denials.
The Washington Post also named Afghanistan and Thailand as hosts of secret jails, which are now said to have closed. Thailand has issued a denial.
The International Committee of the Red Cross has said it wants access to all foreign terror suspects held by the US.