Updated

Serbia is seeking extradition from the U.S. of a naturalized American citizen who is suspected of serving in a Nazi unit that killed around 17,000 Jewish and other civilians during World War II, the justice minister said Friday.

Snezana Malovic told the Associated Press that Serbia sent its formal request for the extradition of Peter Egner earlier Friday.

Belgrade has worked closely with the U.S. on the case of 88-year-old Egner, who was born in Yugoslavia, but emigrated to the U.S. in 1960, gaining American citizenship six years later.

Egner has lived in a retirement community outside Seattle, fighting U.S. federal government efforts to strip him of his American citizenship, which would pave the way for his extradition. The U.S. Justice Department filed a lawsuit in 2008 to revoke Egner's citizenship, saying he failed to disclose details from his past on his naturalization application.

The complaint alleges that Egner served as a guard and interpreter with the Nazi-controlled Security Police and Security Service in Belgrade, Serbia — then Yugoslavia — from April 1941 to September 1943. It says that Egner did not divulge that information when he applied for citizenship, but instead falsely claimed that he served in the German army as an infantry sergeant, and was granted U.S. citizenship in 1966.

Egner has denied any knowledge of the Einsatzgruppe unit that rounded up Jews, political prisoners and other enemies of the Third Reich in the wake of Hitler's attack on the Soviet Union in the early 1940s.

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 murdered 6,280 Serbian Jewish women and children who had been prisoners at Semlin camp. Daily over the course of two months, those women and children were taken from the camp and forced into a specially designed van, in which they were gassed with carbon monoxide.

Serbia's war crimes prosecutor has said that he wants to try Egner in Serbia. The Simon Wiesenthal Center also has encouraged Serbia to try Egner and two other alleged Nazis here.