One of the world's most wanted war criminals, the reputed top lieutenant of Nazi mastermind Adolf Eichmann, is presumed to have died at least four years ago in Syria, where he lived under government protection, a leading Nazi hunter said Monday.

Alois Brunner, an Austrian SS officer found responsible for the World War II deportation of 125,500 European Jews to Nazi death camps, escaped at the war's end from Germany to Egypt and arrived in Syria in 1954, said Efraim Zuroff, head of the Simon Wiesenthal Center's Israel office.

Brunner resided in Damascus under an alias and was employed by the late Syrian President Hafez al-Assad, father of Syria's current ruler, as a terrorism and security expert, Zuroff told Reuters.