Mr Demjanjuk says he was a prisoner of war of the Nazis during World War II
A US judge has blocked an order to deport an alleged Nazi concentration camp guard, two days before he was due to be extradited to Germany.
John Demjanjuk, 89, is accused of involvement in the deaths of 29,000 Jews at a camp in Nazi-occupied Poland.
He denies any involvement and has asked for asylum in the US, arguing that deportation would constitute torture.
An immigration judge said the block would stay until a decision had been reached on whether to re-open his case.
Lawyers for Mr Demjanjuk say his health is far too poor for him to make the journey.
In March, Germany issued an arrest warrant for the Ukraine national over the deaths of thousands of Jews at the Sobibor camp during World War II.
But Mr Demjanjuk, who migrated to the US in 1952, says he was a prisoner of war of the Nazis rather than a prison guard.
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.
German authorities now say they have new evidence linking him to the crimes of which he has been accused.