John Demjanjuk denies the charges against him
A US appeals court has requested more information on the health of a 89-year-old man due to be deported to Germany on war crimes charges.
The removal of John Demjanjuk was halted by the court shortly after he was removed by federal marshals from his Cleveland, Ohio home.
The Justice Department now has until 23 April to tell the court how it decided Mr Demjanjuk was fit to travel.
He denies charges of being a Sobibor death camp guard in World War II.
He claims he was captured by the Germans in his native Ukraine during the war and kept as a prisoner of war.
DEMJANJUK CASE TIMELINE
1952: Gains entry into the US, claiming he spent most of the war as a German prisoner
1977: First charged with war crimes, accused of being "Ivan the Terrible"
1981: Stripped of US citizenship
1986: Extradited to Israel
1993: Israeli Supreme Court overturns conviction, ruling that he is not Ivan the Terrible
2002: Loses US citizenship after a judge said there was proof he worked at Nazi camps
2005: A judge rules in favour of deportation to his native Ukraine
2009: Germany issues an arrest warrant for him; US immigration agents seize him at his home
The request for health information was made by the 6th Circuit US Court of Appeals two days after Mr Demjanjuk had been arrested at his home and taken to a federal building in Cleveland.
It had stopped the deportation, preventing him from being flown to Germany, while it investigated the case further.
Mr Demjanjuk was allowed to return to his home.
He arrived in the US in 1952 as a refugee, settling in Cleveland, where he worked in the car industry.
In 1988, Mr Demjanjuk was sentenced to death in Israel for crimes against humanity after Holocaust survivors identified him as the notorious "Ivan the Terrible", a guard at the Treblinka death camp.
Israel's highest court later overturned his sentence and freed him, after newly unearthed documents from the former Soviet Union indicated that "Ivan the Terrible" had probably been a different man.
Mr Demjanjuk returned to the US, but in 2002 had his US citizenship stripped because of his failure to disclose his work at Nazi camps when he first arrived as a refugee.
In 2005, a US immigration judge ruled that he could be deported to Germany, Poland or Ukraine.
Germany issued a warrant for his arrest last month, and his family have been fighting to prevent him from being deported ever since.
He faces charges of aiding the death of 29,000 Jews.