Kurt Volker has resigned as U.S. special envoy to Ukraine, a source familiar has told ABC News.
News of Volker's resignation was first reported by The State Press, the student newspaper at Arizona State University.
Democrats still are expecting Volker to show up for his deposition on Capitol Hill on Oct. 3, sources tell ABC News.

Kurt Volker, United States Special Representative for Ukraine Negotiations, gestures during an interview in Kiev, Ukraine, Oct. 28, 2017.
Valentyn Ogirenko/Reuters, FILE
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