Washington (CNN) Michael McKinley, the former State Department adviser who resigned last week, is scheduled to testify Wednesday before the congressional committees leading the House impeachment investigation, according to two congressional sources.

U.S. Ambassador to Brazil Michael McKinley speaks during the first edition of the International Brazil Air Show at Tom Jobim international airport, known as Riogaleao, in Rio de Janeiro, Brazil, on March 29, 2017. / AFP PHOTO / YASUYOSHI CHIBA (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images)

McKinley is appearing for a transcribed interview, according to one of the sources, which indicates he is not coming under subpoena.

McKinley's appearance is part of a packed week for the House Intelligence, Foreign Affairs and Oversight Committees conducting the impeachment inquiry into President Donald Trump and Russia, with as many as five current and former administration officials appearing this week. The committees are turning their scope beyond just the State Department with their first witness scheduled from the Pentagon.

The pace of the witness interviews signals how the committees are trying to work as expeditiously as possible to gather information as part of the investigation into the President's July call with Ukrainian President Volodymyr Zelensky, the push for an investigation into Vice President Joe Biden and his son and the freezing of US aid to Ukraine.

The committees also have a host of deadlines for documents to be turned over this week -- including from government agencies and the President's personal attorney Rudy Giuliani -- although it's unclear how much compliance they will get given the White House's stance that the probe is illegitimate.

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