JERUSALEM, June 2 (Reuters) - The Nazi-hunting Simon Wiesenthal Centre urged Austria on Thursday to prosecute a war crimes suspect who recently fled Croatia to southern Austria.

Milivoj Asner, 92, is on the centre's top 10 list of alleged Nazi accomplices sought under a "Last Chance" campaign launched last year to track down the last surviving suspects of Holocaust-era crimes against Jews and other minorities.

Asner fled Croatia last year shortly after being named as a target of the campaign, and was recently spotted in Klagenfurt, capital of the southern Austrian province of Carinthia, Efraim Zuroff, the centre's director in Israel, said.

"He played a very active role" in persecutions and deportations of hundreds of Jews, Serbs and Gypsies, to Nazi concentration camps as police chief in Slavonska Pozega, a city run by the Nazi-allied Croat Ustashe regime in World War II, Zuroff said.

Among the millions killed in Europe under Nazi persecution in the 1940's, six million Jews died under Adolf Hitler's "final solution" plan.

In a letter to Austria's Ambassador to Israel, Kurt Hengel, Zuroff wrote that "Asner's presence in Klagenfurt has been well-known to the Austrian authorities for months, but yet they have not taken any legal action against him."

Zuroff told Reuters there was "enormous" documentation available to prosecute Asner.

"You have to send a message that people like this belong in jail ... The passage of time has in no way diminished the culpability of perpetrators" of war crimes," Zuroff said.

Last year Zagreb had pledged to take steps to prevent Asner from fleeing Croatia. Zuroff said he was concerned that Croatia had not yet asked Austria to extradite him.

In Vienna, an Austrian Interior Ministry spokesman said Asner had both Austrian and Croatian citizenship and that he had returned to the country "but we have no specific details because there is no reason for us to take surveillance measures."

It would be up to prosecutors in Klagenfurt to decide whether to take legal action against Asner, the Austrian spokesman said.

Prosecutors in Klagenfurt could not be reached for comment.

(Additional reporting by Francois Murphy in Vienna)

REUTERS, June 2, 2005