A 94-year-old former SS sergeant has told a German court he is "ashamed" that he served as a guard in the Nazis' Auschwitz death camp and that he knew what was going on there but did nothing to stop it.

Reinhold Hanning told the Detmold state court Friday that he had never talked about his service in Auschwitz from January 1942 to June 1944, even to family, but wanted to use his trial as an opportunity to apologize.

"I want to say that it disturbs me deeply that I was part of such a criminal organization," he said. "I am ashamed that I saw injustice and never did anything about it and I apologize for my actions. I am very, very sorry."

Hanning faces 170,000 counts of accessory to murder.