WARSAW, Poland — Polish prosecutors said they are working on a request for the extradition from the U.S. of a Minnesota man they accuse of participating in a World War II massacre.

The Associated Press had previously identified the man as 98-year-old Michael Karkoc, an ex-commander in an SS-led Nazi unit that burned Polish villages and killed civilians during the war.

Prosecutor Robert Janicki of Poland’s National Remembrance Institute told The Associated Press on Wednesday that the extradition request will be sent to the U.S. Justice Department soon, but declined to specify when.

Poland asked U.S. justice authorities for assistance in having Karkoc medically examined to make sure he can take part in court proceedings.