BRUSSELS, Belgium – The CIA has conducted more than 1,000 clandestine flights in Europe since 2001, and some of them secretly took away terror suspects to countries where they could face torture, European Union lawmakers said Wednesday.

Legislators selected to look into allegations of questionable CIA activities in Europe said flight data showed a pattern of hidden operations by American agents, and they accused some European governments of knowing about it, but remaining silent.

Cases of terror suspects being secretly handed over to U.S. agents did not appear to be isolated, the lawmakers said in a preliminary report on their inquiry. European human rights treaties prohibit sending suspects to states known to torture prisoners.

“The committee deplores the fact that, as established during the committee’s investigation, the CIA has used aircraft registered under fictitious company names or with private companies to secretly transfer terror suspects to other countries including Egypt, Jordan, Syria and Afghanistan,” according to a copy of the report obtained by The Associated Press.

The CIA declined to comment, as did European Union officials, who have said previously that there was no irrefutable proof of such hand-overs, which are known as “extraordinary renditions.”

The investigation began in January after news reports that U.S. agents had interrogated al-Qaida suspects at secret prisons in eastern Europe. But the focus shifted after people gave detailed accounts of being abducted by U.S. agents in Europe and whisked away to jails in the Middle East, Asia and North Africa.

Few of those who testified at the committee hearings touched on the alleged secret prisons in eastern Europe first reported by The Washington Post in November. Italian lawmaker Giovanni Fava, who wrote the report, said the committee would look into those allegations later.

The lawmakers based their initial report on data provided by Eurocontrol, the EU’s air safety agency, and more than 50 hours of testimony by EU officials, rights groups and individuals who said they were kidnapped and tortured by U.S. agents.

Eurocontrol said the number of clandestine CIA flights over Europe was likely to be higher than 1,000 because the agency checked only flight plans for fewer than 50 aircraft used by the CIA.

“We were requested by EU Parliament to make an analysis of the flight routes for these planes. There may be others,” said Jean-Jacques Sauvage, senior official for the Brussels-based agency. He said Eurocontrol did not keep track of who was on the planes.

The report said that on a number of occasions, the CIA was clearly responsible for detaining terror suspects on European territory and transferring them to countries where they could face torture.

Fava told the AP it was unclear how many people were transferred by the CIA on undeclared flights. He also said there was no evidence proving complicity by European officials, but called it unlikely that some governments, such as in Italy, Bosnia and Sweden, knew nothing about the CIA operations.

He accused the CIA of breaching the Chicago Convention, an international treaty governing air traffic. It requires aircraft used in military, customs and police operations to seek special authorization to land in signatory states.

U.S. officials previously said that as of late December, some 100 to 150 people had been seized in “rendition” operations.