John Demjanjuk has been officially charged with helping murder nearly 28,000 Jews during the second world war.

German prosecutors on Monday charged Demjanjuk, 89, with "complicity to murder" over the deaths of 27,900 Jews in the Nazi-run Sobibor camp in Poland.

Ukrainian-born Demjanjuk is alleged to have been a guard at the camp, but defence lawyers say he was never at Sobibor.

Efraim Zuroff, head of the Wiesenthal Centre in Jerusalem, a Jewish human rights group, said: "This is a milestone on the way to finally achieving justice.

"A trial of this sort sends a very important message that even many years after the crimes were committed, it is still possible to achieve justice."

Demjanjuk was deported from the United States, where he had lived since becoming a refugee in 1952, in May.

At the beginning of July, doctors assessed him as being fit to stand trial as long as court sessions do not exceed two 90-minute hearings a day. His family had argued that he was too frail.

The trial could start in the city of Munich as early as this autumn although no date has been set.

Demjanjuk's lawyer made no immediate comment on the charges.