Nazi war criminal Alois Brunner is believed to have died in Syria

The man who was once the world's most-wanted Nazi war criminal, Alois Brunner, is "almost certain" to have died in Syria four years ago, a Nazi-hunting group said.

"I am almost certain that he's no longer alive," said Efraim Zuroff, director of the Simon Wiesenthal Centre's Jerusalem office.

Zuroff said that according to a German intelligence officer, Brunner "died four years ago in ... Damascus," where he had fled seeking refuge decades ago.

The Wiesenthal Centre "could not confirm the information" for certain, he stressed, but given the 1912 birth year of Brunner, the unrepentant "right-hand man" of leading Holocaust architect Adolf Eichmann, he was in any case unlikely to be alive.

Brunner topped the Simon Wiesenthal list of wanted Nazis for deporting tens of thousands of Jews to death camps during the second world war, although he was removed this year due to his age and almost certain death, Zuroff said.

After the war Brunner escaped detection by taking on a false identity and worked for two years for the US occupying forces in Germany, before fleeing to Egypt in 1954 and from there to Syria, where he was protected by successive regimes.