MEPs believe European countries colluded with the US in facilitating CIA torture flights.
The European Parliament committee investigating so-called rendition flights across Europe say that up to 50 people were moved across Europe to jails in countries where they faced torture and other abuses, MEPs told a news conference this afternoon.
Referring to a recent trip to Washington as part of their investigation, Portuguese MEP Carlos Coelho said: "All the people we met [in the United States] suggested or confirmed that the programme of renditions in Europe could not have been carried out without the knowledge and support of the governments".
"Officials from the State Department told us, in more diplomatic terms, that the United States had never violated the sovereignty of European Union member states.
"Others admitted the European governments' involvement more directly," said Mr Coelho.
Claudio Fava from Italy said 30 to 50 people had been handed over by the United States since September 11 and the launch of the US "war on terror".
"We also have confirmation from a reliable source within the CIA that the sequestration of Abu Omar in Milan could not have happened without the knowledge of the Italian intelligence services," Mr Fava said.
Italian and German prosecutors are investigating the case of Mr Omar, an Egyptian man they believe was snatched on a Milan street by a team of CIA agents in February 2003 and flown via Germany to Egypt, where he later said he was tortured.
A German national, Khaled el-Masri, is suing the former head of the CIA over his alleged rendition from Macedonia to Afghanistan, where he says the US held him in jail for months as a terrorist suspect in 2004.
German prosecutors are also investigating the claim.
Sweden's parliamentary ombudsman has criticised the security services over the expulsion of two Egyptian terrorism suspects who were handed over to US agents and flown home aboard a US government-leased plane in 2001.
Dick Marty, a Swiss investigator from the Council of Europe human rights watchdog which is separately investigating the renditions, which he calls the "outsourcing of torture".