Story here; an excerpt:

The CIA has been hiding and interrogating some of its most important al Qaeda captives at a Soviet-era compound in Eastern Europe, according to U.S. and foreign officials familiar with the arrangement.

The secret facility is part of a covert prison system set up by the CIA nearly four years ago that at various times has included sites in eight countries, including Thailand, Afghanistan and several democracies in Eastern Europe, as well as a small center at the Guantanamo Bay prison in Cuba, according to current and former intelligence officials and diplomats from three continents.

The hidden global internment network is a central element in the CIA’s unconventional war on terrorism. It depends on the cooperation of foreign intelligence services, and on keeping even basic information about the system secret from the public, foreign officials and nearly all members of Congress charged with overseeing the CIA’s covert actions.

The existence and locations of the facilities — referred to as "black sites" in classified White House, CIA, Justice Department and congressional documents — are known to only a handful of officials in the United States and, usually, only to the president and a few top intelligence officers in each host country.

The CIA and the White House, citing national security concerns and the value of the program, have dissuaded Congress from demanding that the agency answer questions in open testimony about the conditions under which captives are held. Virtually nothing is known about who is kept in the facilities, what interrogation methods are employed with them, or how decisions are made about whether they should be detained or for how long.

While the Defense Department has produced volumes of public reports and testimony about its detention practices and rules after the abuse scandals at Iraq’s Abu Ghraib prison and at Guantanamo Bay, the CIA has not even acknowledged the existence of its black sites. To do so, say officials familiar with the program, could open the U.S. government to legal challenges, particularly in foreign courts, and increase the risk of political condemnation at home and abroad.

But the revelations of widespread prisoner abuse in Afghanistan and Iraq by the U.S. military — which operates under published rules and transparent oversight of Congress — have increased concern among lawmakers, foreign governments and human rights groups about the opaque CIA system. Those concerns escalated last month, when Vice President Cheney and CIA Director Porter J. Goss asked Congress to exempt CIA employees from legislation already endorsed by 90 senators that would bar cruel and degrading treatment of any prisoner in U.S. custody.