Poland is seeking the extradition of a Minnesota man accused of being a Nazi SS lieutenant responsible for the killing of 44 Poles.

Michael Karkoc, 98, allegedly ordered the murder of civilians in the Polish villages of Chlaniow and Wladyslawin in July 1944 while heading a unit in the SS-led Ukrainian Self Defence Legion.

Prosecutor Robert Janicki said there was conclusive evidence to prove Mr Karkoc, who now lives in America, ordered the massacre.

He said the evidence had been collected from years of investigations and confirmed Mr Karkoc’s identity "100 per cent".

Prosecutors have applied to a regional court in Lublin to issue a warrant for his arrest.

If granted, Poland will seek the extradition of Mr Karkoc to face trial.

Mr Janicki said: "He is our suspect as of today."

He was investigated by German authorities in 2013 after the Associated Press alleged he was a former Nazi commander.

But the probe was stopped in 2015 after prosecutors said they had received evidence suggesting he was not well enough to stand trial.

Mr Karkoc's family has denied he was involved in any war crimes.

His son, Andriy Karkoc, said his father was not in Poland at the time and was not behind any war crimes.

He accused Russian President Vladimir Putin's government of making up the stories of "misinformation or disinformation" about his father.

Efraim Zuroff, a Nazi-hunter at the Simon Wiesenthal Centre, praised Polish authorities for pursuing legal action.

He told the AP: "It's high time that the Poles became more active seeking people who committed crimes in the Second World War on Polish soil".

Stephen Ankier, one of Britain’s leading experts in the hunt for Second World War criminals, told the JC in 2014 he had also been investigating Mr Karkoc.