The US Justice Department has asked a federal court to revoke the citizenship of an 86-year-old man it says served in a Nazi unit. A complaint filed Tuesday in Seattle says Peter Egner served as a guard and interpreter with the Security Police and Security Service in Yugoslavia during World War II. The unit slaughtered 17,000 Serbian civilians. The Justice Department said Egner did not divulge the information when he moved to the United States in 1960 or when he gained citizenship in 1966. He denies serving with the Nazis.