Mr Demjanjuk says he was a prisoner of war of the Nazis
German prosecutors have filed charges against an alleged Nazi death camp guard who lives in the United States, and have applied for his extradition.
John Demjanjuk, 88, is accused of involvement in the deaths of 29,000 Jews at a camp in Nazi-occupied Poland.
Mr Demjanjuk was sentenced to death in Israel in the 1980s, but was then acquitted and returned to the US.
He denies any involvement in the crimes, saying he was a prisoner of war of the Nazis, rather than a guard.
German authorities said on Wednesday that they had charged Mr Demjanjuk with more than 29,000 counts of accessory to murder, according to the Associated Press.
'Ivan the Terrible'
In November last year investigators in Munich, where Mr Demjanjuk lived briefly after the war, said they had managed "to obtain hundreds of documents and have also found a number of witnesses who spoke out against Demjanjuk".
"For the first time we have even found lists of names of the people who Demjanjuk personally led into the gas chambers. We have no doubt that he is responsible for the death of over 29,000 Jews", said Kurt Schrimm, who heads the special German office investigating Nazi crimes.
Ivan Demjanjuk was born in Ukraine and migrated to the US in 1952.
In 1986, he was extradited to Israel and sentenced to death for war crimes, after being identified by witnesses as "Ivan the Terrible" - a notorious prison guard at the Treblinka camp.
But the Israeli Supreme Court overturned his conviction, when new evidence emerged suggesting he was not the same guard.
He returned to the US but was accused of lying on his immigration application about working for the Nazis.
In 2002, a US immigration judge ruled that there was enough evidence to prove Mr Demjanjuk had been a guard at several Nazi death camps and stripped him of his citizenship.
Last year, the retired Ohio car worker lost his legal fight to stay in the US, when the US Supreme Court rejected his appeal against deportation. He remained in the US, however, while authorities tried to decide where he should be sent.