A US judge has upheld a deportation order for a man described as an "indispensable" part of the Nazi campaign in the Ukraine.

John Kalymon was found to have voluntarily served in the Nazi-sponsored Ukrainian Auxiliary Police for three years during the Holocaust.

He moved to the US four years after the war ended, gained US citizenship and settled in Michigan, where he worked in a Chrysler factory. In 2007 he was stripped of his citizenship for concealing his wartime collaboration and last January a judge ordered that the 90-year-old should be deported.

The US Justice Department said Kalymon "personally shot Jews" and took part in "lethal acts of Nazi-sponsored persecution" and "violent anti-Jewish operations in which Jews were forcibly deported to be murdered in gas chambers and to serve as slave labourers".

Assistant Attorney General Lanny Breuer added that Kalymon and his Ukrainian police accomplices "were indispensable participants in Nazi Germany's campaign to exterminate the Jews of Europe".

Around 900,000 Jews were killed in the Ukraine during the Holocaust. The figure was some 60 per cent of the country's pre-war Jewish population.

If Kalymon is successfully deported, he could go to Germany. In May the Ukrainian-born John Demjanjuk was convicted , in a German court, of Nazi-era war crimes.