Updated

Federal prosecutors say one of Ukraine's most influential oligarchs faces a corruption charge in Chicago.

The U.S. attorney's office said in a brief statement Friday that 48-year-old Dmytro Firtash has been charged in an "international corruption conspiracy." It said he was arrested this week in Vienna and the government is seeking his extradition.

Prosecutors offered few details. They did add "Firtash's arrest is not related to recent events in Ukraine." Russia sent forces into Ukraine's Crimea region, challenging a pro-European government in Kiev.

The statement says Firtash controls a conglomerate of companies called Group DF, but adds nothing about the allegations or if they are related to Group DF. And no court papers had been filed in Chicago as of Friday evening.

U.S. prosecutors spell Firtash's first name as Dmitry.