A former Nazi concentration camp guard identified as Josef S has been given a five-year jail term for assisting in the murder of thousands of prisoners at Sachsenhausen near Berlin.

The oldest Nazi criminal ever to stand trial in a German court, he had always denied being an SS guard at the camp.

He was found guilty of aiding and abetting the murders of 3,518 people.

He was complicit in the shooting of Soviet prisoners of war and the murder of others with Zyklon B gas.

The defence had called for his acquittal and is set to appeal against the prison sentence.

Tens of thousands of people died at Sachsenhausen during World War Two from starvation, forced labour, medical experiments and murder by the SS. More than 200,000 people were imprisoned there, including political prisoners as well as Jews, Roma and Sinti (Gypsies).

"I don't know why I'm sitting here in the sin bin. I really had nothing to do with it," Josef S said in his closing statement on the eve of the verdict in Brandenburg an der Havel.

Judge Udo Lechtermann told him that despite his claims to the contrary the court had found that he had worked at the concentration camp for around three years from 1942. "You willingly supported this mass extermination through your occupation," he said.

Putting Nazi camp guards on trial only became possible in 2011, when ex-SS guard John Demjanjuk was found guilty. That verdict prompted a search for individuals who were still alive.

Four years later, the so-called "bookkeeper of Auschwitz", Oskar Gröning, was given a jail term. And a 97-year-old former concentration camp secretary is currently on trial in northern Germany.

Josef S is not fully identified in Germany because of privacy conventions. Although his name and birth details were given on the documents of an SS guard, he claimed he had not been at the camp and worked instead as a farm labourer.

He is unlikely to serve any of his sentence as Germany's highest court will first have to rule whether to allow his appeal, and that will take several months.