He was extradited to Israel in 1986, and sentenced to death for being the infamous operator of the gas chamber at Treblinka extermination camp.

But his sentence was quashed in 1993 when evidence was produced that Ivan had been another man.

Mr Demjanjuk now faces charges filed by the US Justice Department that he was a camp guard at the Sobibor extermination camp, and at the Majdanek and Flossenburg concentation camps.

Mr Demjanjuk, who is 79, has denied he had anything to do with the Nazi extermination of Jews during World War II, and says he has been the victim of a case of mistaken identity.

The US appeals court severely rebuked the Justice Department for its initial handling of the Demjanjuk case, saying it deliberately withheld evidence undermining claims that Demjanjuk was Treblinka's gas chamber operator.

Wartime activities

To win this case, the Justice Department needs to proove that Demjanjuk lied about his wartime activities when he obtained a visa to enter the US.

The 15-page lawsuit alleges that Mr Demjanjuk was recruited by the Nazis in 1942 at the Trawniki training camp in Poland, from where he joined "Operation Reinhard," a programme to exterminate Polish Jews.

He has always maintained he spent the war working on a farm in Poland and as a labourer in Germany.

After his conviction for working at Treblinka was overturned by the Israeli supreme court, he returned to Cleveland, Ohio where he had lived in the US.