Three Holocaust survivors provided grim testimonies at the trial of 94-year-old former Auschwitz guard Reinhold Hanning in Detmold, Germany, last week.

The former Auschwitz guard and SS sergeant is suspected of working in the Nazi death camp during the "Hungarian Action" in 1944, when thousands of Hungarian Jews were gassed. He is accused of being an accessory to murder on 170,000 counts.

Hanning admitted he was a guard at Auschwitz but denied taking part in any executions.

Justin Sonder, the youngest of the witnesses at 90, arrived at Auschwitz at 17. He was selected to be a slave labourer for the IG Farben company, rather than sent directly to the gas chambers.

According to AP, he told the court that after three or four months, he was considered one of the "older" prisoners. He added that he most feared selection days, when SS guards lined up naked inmates for up to four hours to decide who was fit to work and who should be killed.

"I don't have the words to describe how it was, when you know that you could be dead in one or two hours, it made you sick, made you crazy," he said.

"I survived 17 selections," added Mr Sonder, who lost 22 family members in the Holocaust.

Hanning, who appears in good health for his age, has spoken only one word so far, telling judge Anke Grudda that he was "good" when she asked how he was after the first day of the trial.

Survivor Erna de Vries, whose father was not Jewish, told the court when the Nazis came for her Jewish mother in 1943 she did not have to go with her to Auschwitz but chose to stay with her.

She was in Auschwitz for only two months when the SS took her and about 85 other people to the women's concentration camp Ravensbruck.

"That was one of the worst days of my life when I was sent to Ravensbruck and my mother stayed in Auschwitz," she said. "I never saw her again."

Leon Schwarzbaum, a 94-year-old Auschwitz survivor from Berlin who was used as a slave labourer, said he could not see the area with the gas chambers and crematoria from where he was kept, but that everyone knew exactly what was going on there.

The trial continues this week.