But Swiss senator Dick Marty said that there was no formal proof so far of the existence of clandestine detention centers in Romania or Poland as alleged by the New York-based Human Rights Watch.
"There is a great deal of coherent, convergent evidence pointing to the existence of a system of "relocation" or "outsourcing" of torture," Marty said in a report presented to the Council of Europe, the human rights watchdog on whose behalf he is investigating.
"Acts of torture or severe violation of detainees' dignity through the administration of inhuman or degrading treatment are carried outside national territory and beyond the authority of national intelligence services."
The report said more than 100 terror suspects may have been transferred to countries where they faced torture or ill treatment in recent years.
"The entire continent is involved," Marty told the Council of Europe's parliamentary assembly, a body comprising several hundred national parliamentarians. "It is highly unlikely that European governments, or at least their intelligence services, were unaware."
In the report, Marty analyzed the cases of an Egyptian cleric allegedly kidnapped from Milan, Italy, in 2003 by CIA agents and a German captured in Macedonia and taken to Afghanistan in an apparent case of mistaken identity.
Citing an American lawyer, Marty also said six Bosnians were abducted by American agents on Bosnian soil and taken to Guantanamo Bay, despite a Bosnia judgment ordering their release.
Last week, Italy's justice minister formally asked the United States to allow Italian prosecutors to question 22 purported CIA operatives they accuse of kidnapping the Egyptian cleric, Osama Moustafa Hassan Nasr, in 2003 from a Milan street.
Nasr, believed to belong to an Islamic terror group, was seized on Feb. 17, 2003. Prosecutors claim the cleric, who is also known as Abu Omar, was taken by the CIA to a joint U.S.-Italian air base, flown to Germany and then to Egypt, where he says he was tortured.