Former SS officer Oskar Groening, known as the "bookkeeper of Auschwitz", admitted at his trial Tuesday to "moral guilt" over the mass murder at the death camp and asked for "forgiveness".

"For me there's no question that I share moral guilt," the 93-year-old told the judges, admitting that he knew about the gassing of Jews.

"I ask for forgiveness," he told the court, attended by Holocaust survivors. "You have to decide on my legal culpability."