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.
(MORE: House Democrats subpoena Pompeo for documents related to Giuliani's Ukraine efforts)Democrats still are expecting Volker to show up for his deposition on Capitol Hill on Oct. 3, sources tell ABC News.
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