Suspected Nazi war criminal John Demjanjuk is fit enough to be held in jail until such time as he goes on trial, German prison doctors say.
Mr Demjanjuk, 89, was flown to Germany on Tuesday from the United States, where he waged a long battle against deportation, partly on health grounds.
But a spokesman for Stadelheim jail in Munich said "doctors have determined he is fit to remain in custody".
He faces charges of being an accessory to the deaths of 29,000 Jews.
The arrest warrant was read to him hours after his arrival in Germany.
His lawyer, Guenter Maull, said the suspect had sat in a chair while the 21-page warrant was read and translated into his native Ukrainian language.
Mr Demjanjuk "showed no emotion, with few facial movements" but had understood the charges, he said.
He denies accusations that he worked as a guard in the Sobibor Nazi death camp in Poland during World War II.
Mr Demjanjuk, who settled in the US in 1952, says he was captured by the Germans in his native Ukraine during the war and kept as a prisoner of war.
'In good shape'
He is being kept under medical observation to allow experts to determine whether he is fit to go to trial - an assessment which may take weeks.
But deputy prison director Jochen Menzel said Mr Demjanjuk was in strikingly good condition.
"He is not typical for his age... he is in better shape than usual for an 89-year-old," he told German news channel N24.
His lawyers had argued in US courts that he was too frail to be deported, but the US government, which secretly shot footage showing him walking without assistance, argued he was fit to travel.
An appeals court ruled against him, saying it was satisfied that he would be provided with adequate care.
Mr Demjanjuk arrived in the US in 1952 as a refugee, settling in Cleveland, Ohio, where he worked in the car industry.
In 1988 he was sentenced to death in Israel for crimes against humanity, after Holocaust survivors identified him as a notorious guard at the Treblinka death camp. But the Israeli Supreme Court overturned that conviction and he returned to the US.
Prosecutors now say they have documents which prove his Nazi background, including an SS identity card which shows he was posted to the death camp in Sobibor in 1943, and many witness testimonies.
Mr Demjanjuk's deportation was welcomed by observers.
Wolfgang Benz, head of the Centre for Anti-Semitism Research at Berlin university, welcomed Mr Demjanjuk's deportation.
"This is about guilt, about avenging a crime, about responsibility for a criminal act," he told told Deutschlandfunk public radio.
"Whether this old man who possibly is in a pathetic state spends his last years in a prison hospital or does not serve his sentence due to ill health, that's of secondary importance."