A group of European Union lawmakers sought Tuesday to find out from U.S. officials, lawmakers and human rights groups whether any European countries were involved in secret CIA prisons or flights for terror suspects.

Clandestine prisons and secret flights via or from Europe to countries where suspects could face torture would breach the EU's human rights conventions. So far, no senior EU official or government leader has confirmed questionable or illegal CIA activities on European territory.

The deputy chairman of the 13-member group, German deputy Cem Ozdemir, said the purpose of the four-day Washington trip is not to question activities of the Central Intelligence Agency, but to determine the involvement of European countries.

"We want to find out more about accusations that it is very likely secret prisons existed in Poland and Romania, but so far the smoking gun is not there," he said at the start of a meeting with two American lawyers specializing in international law and human rights. Poland is a member of the 25-nation EU, and Romania is seeking to join.

Another member of the delegation, British deputy Jean Lambert, said the purpose of the trip "is basically fact-finding. We'd like to get some clear answers on the involvement of European governments" in the alleged prisons and overflights.

The delegation is scheduled to meet with Assistant Secretary of State for European Affairs Daniel Fried, former CIA director James Woolsey and several members of Congress. They also will meet with John Bellinger, legal adviser to Secretary of State Condoleezza Rice.

Allegations that the CIA shipped prisoners through European airports to secret detention centers, including compounds in eastern Europe, were first reported by the Washington Post last November.

Last month, the EU lawmakers said data from the EU's air traffic agency show there have been more than 1,000 clandestine CIA flights stopping on European territory since the Sept. 11, 2001, attacks in the United States. But they said it was not clear if or how many detainees were on board.

In Brussels last week, Bellinger did not deny there have been CIA flights over Europe or ones with stopovers, but he dismissed implications that they all carried detainees. He said the flights may have carried intelligence experts, counterterrorism officials or forensic evidence.