BELGRADE, Serbia (AP) — Serbia's war crimes court is investigating genocide allegations against a man accused of serving as a Nazi officer before emigrating to the United States and retiring outside Seattle.

The court said Friday that 86-year-old Peter Egner, who lives in a suburban retirement community, is suspected of committing genocide and other war crimes against civilians in Belgrade while serving as a Nazi officer during the occupation of Serbia in 1941-44.

The court offered no more details about Egner's alleged role in the atrocities. The opening of an investigation is a key step toward formal indictment and a trial.

Serbia has said it would seek Egner's extradition from the United States. The head of the Israeli branch of the Simon Wiesenthal Center this month encouraged Serbia to try Egner and two more alleged Nazis here.

The U.S. Justice Department asked a federal court in July to revoke Egner's American citizenship because he had not disclosed details about his past when he applied for the citizenship.

Egner immigrated to the U.S. in 1960 and applied for citizenship, the complaint said. Officials say he falsely claimed that he served as a rank-and-file infantry sergeant in the German army, and he was granted U.S. citizenship in 1966.

Egner's lawyer Robert Gibbs this month asked a federal judge to reject the demand. He said Egner denies any involvement in wartime mistreatment and is being accused of atrocities committed by others.

Revoking Egner's U.S. citizenship would pave the way for his extradition to Serbia.

Egner is accused of being a guard and interpreter for a Nazi squad that killed thousand of Jews, Gypsies and political dissidents in Belgrade.

The Justice Department, citing Nazi documents, said that in the fall of 1941, Egner's unit executed 11,164 people — mostly Serbian Jewish men, suspected communists and Gypsies — and that in early 1942, it killed 6,280 Serbian Jewish women and children who were held as prisoners. In two months, those women and children allegedly were taken from the camp and forced into an especially designed van, in which they were gassed with carbon monoxide.

Serbian war crimes prosecutor's office has said it was working closely with American officials on Egner's case.

The war crimes court noted in its statement Friday that "any delay could prevent efficient conduct of this investigation" because of the advanced age of Egner and any possible witnesses.

Associated Press