The Nazi-hunting Simon Wiesenthal Center will launch a campaign in Germany this summer to flush out the last surviving Nazi war criminals, Efraim Zuroff, the center's Jerusalem head, said in a magazine interview on Sunday.

The Jewish rights group will offer 10,000 euro ($11,800) rewards for leads that result in a conviction, and will appeal for information in newspaper adverts, Zuroff told Focus magazine.

The campaign is part of "Operation Last Chance", a drive to catch World War Two criminals which is already underway in the three Baltic states, as well as Romania, Poland and Austria.

"There are still thousands of war criminals in Europe," Zuroff said. "We're going wherever Jews were murdered. Those countries also have the most witnesses."

The Simon Wiesenthal Center is racing against time as both
the perpetrators and survivors of war crimes grow old and die. Zuroff told Reuters last year there was a "window of opportunity" of three-five more years to catch Nazi criminals.

The Center last year said eastern European states in particular needed to step up their efforts to try suspected war criminals. It recognized achievements made in Germany in pursuing perpetrators. There are close to 500 ongoing investigations into suspected Nazi war criminals and the fact that most suspects are at least in their 80s makes trying them a priority.

Among the cases, three former German SS officers, all in their 80s, went on trial in absentia in an Italian court last month accused of taking part in the massacre of 560 Tuscan villagers during World War Two. The three did not travel to Italy and it was unclear if they could be extradited.

Britain this year awarded an honorary knighthood to Simon Wiesenthal, 95, for "a lifetime of service to humanity" pursuing Holocaust perpetrators. He spent the best part of five decades tracking down more than 1,000 Nazi war criminals responsible for the mass murder of Jews in World War Two and played a role in the capture of Adolf Hitler's close associate Adolf Eichmann.

He said last year he felt his work was complete. "I found the mass murderers I was looking for, and I have outlived all of them," he told an Austrian magazine. "If there's a few I didn't look for, they are now too old and fragile to stand trial. My work is done."