Khaled al-Masri says he was kidnapped in 2003 while on holiday in Macedonia and flown to Afghanistan, where he was held for five months and mistreated.

German Foreign Minister Frank-Walter Steinmeier said the authorities learned of the case only after Mr Masri contacted them following his release.

The US secretary of state has said that the US would never condone torture.

Washington has come under pressure over media allegations that the CIA ran secret jails abroad for terror suspects and flew some through European airports.

Mr Masri is suing the CIA for wrongful imprisonment and abuse.

'Nauseated'

Mr Steinmeier told parliament he was "nauseated" by reports suggesting the Germans had helped the US to catch Mr Masri by providing information on him.

"Let me make it clear: the government and [security services] did not aid and abet the abduction," he said.

Mr Steinmeier said the government had alerted German prosecutors after learning of the case in June 2004, and had repeatedly asked the US for information.

US Secretary of State Condoleezza Rice has repeated assurances that the US would never condone torture.

A European investigator said on Tuesday that allegations the CIA abducted and illegally transported terror suspects across European borders were credible.

Swiss senator Dick Marty submitted a report on the claims to a meeting of the human rights committee of the Council of Europe.

On Wednesday, European Union Justice and Security Commissioner Franco Frattini appeared to contradict Mr Marty's findings.

"At the moment, there is no evidence confirming the allegations made," he told the European Parliament, which is considering whether to set up its own inquiry.