The head of a European probe into alleged secret CIA prisons in eastern Europe is investigating 31 suspected flights that landed in Europe and is trying to acquire past satellite images of sites in Romania and Poland, according to a report obtained by The Associated Press Tuesday.

Dick Marty, a Swiss senator leading the investigation for the Council of Europe, presented a first report on his work at a closed meeting of the human rights watchdog's legal affairs committee in Paris.

Marty said he had asked the Brussels-based Eurocontrol air safety organization to provide details of the 31 suspected flights, a list of which was given to him by the New York-based Human Rights Watch.

"I received from Human Rights Watch a list of 31 aircraft alleged to belong to entities with direct or indirect links to the CIA," Marty said in the report, to be made public next week. "It is claimed these were used by the CIA to transport prisoners."

In an interview with the AP, Marty said there was still no direct proof that secret prisons existed anywhere in Europe, but that there were "many hints, such as suspicious moving patterns of aircraft, that have to be investigated."

Marty said he had asked the European Union's Satellite Center in Spain to look up and hand over satellite images of locations in Romania and Poland that were cited by Human Rights Watch as sites of possible CIA secret prisons.

"When we talk about 'prisons,' they don't necessarily have to be for many people, they could be cells for a very small group of people," he said.

Human Rights Watch identified the Kogalniceanu military airfield in Romania and Poland's Szczytno-Szymany airport as likely sites for secret detention centers. The group says it based its conclusion on flight logs of CIA aircraft from 2001 to 2004 that it had obtained.

Other airports that might have been used by CIA aircraft in some capacity are Palma de Majorca, Larnaca in Cyprus and Shannon in Ireland, Marty's report says.

Allegations that the CIA hid and interrogated key al-Qaida suspects at Soviet-era compounds in Eastern Europe were first reported in The Washington Post on Nov. 2. The paper did not name the countries involved. A day after the report appeared, Human Rights Watch said it had evidence indicating the CIA transported suspected terrorists captured in Afghanistan to Poland and Romania.

The parliamentary assembly of the Council appointed Marty two weeks ago to investigate the paper's claims. Marty said the Council had a "moral obligation" to investigate the claims, but that the probe was not meant to spark anti-American feelings or question the United States' fight against terrorism.

"This is absolutely not a crusade against America. I think all Europeans agree with Americans that we must fight terrorism, all Europeans lived through 9/11 with Americans," he said. "We do not want to weaken the fight against terrorism ... but this fight has to be fought by legal means. Wrongdoing only gives ammunition to both the terrorists and their sympathizers."

Brussels-based Eurocontrol — also known as the European Organization for the Safety of Air Navigation — develops, coordinates and plans pan-European air traffic management strategies. Member states send Eurocontrol their flight logs — of both civilian and military flights — but do not publish them.