(CNN) Former US Special Envoy for Ukraine Kurt Volker plans to appear at his deposition next Thursday in front of three congressional committees, according to a source familiar with his plans.

The source would not say if the White House is seeking to use executive privilege to constrict Volker in terms of what he can say or provide.

Volker's appearance before the Intelligence, Oversight and Reform and Foreign Affairs committees was announced just hours before the news broke Friday evening that he had resigned

Volker didn't offer a comment when contacted Saturday by CNN.

The former US special envoy is expected to face tough questioning after finding himself in the middle of the controversy surrounding the intelligence whistleblower who had alleged a coverup by the White House over a call made by President Donald Trump to Ukrainian President Volodymyr Zelensky. That whistleblower also mentioned Volker's name in his complain t when discussing interactions between himself and Trump's personal attorney, Rudy Giuliani, concerning pushing Ukraine to look into activities of Joe Biden's son, Hunter.

There is no evidence of wrongdoing by Joe or Hunter Biden.

Depositions are generally closed door, but the committees have not clarified if Volker's deposition will be open or closed.

The deadline for Secretary of State Mike Pompeo to produce documents from the State Department on this matter after being subpoenaed by three congressional committees is after Volker is set to appear. The sequence here appears strange because usually investigators want to have documents in hand before interviews.

Aides on the Hill are not expressing any interest in delaying the deposition. The House Foreign Affairs Committee is also not confirming whether or not four other State Department officials involved in the Ukraine controversy in different ways are all confirmed to show up on the dates the committee announced for depositions which are set to take place over the next two weeks.

Some White House officials see Volker's departure as being motivated by him believing he needed to protect the McCain Institute, where he also maintained a role during his time as special representative to Ukraine, explained one source familiar with discussions at the White House.

Generally, there is not much love lost for Volker by White House officials, whom another source says "was never fully on the Trump train."

CLARIFICATION: This story and headline have been updated to make clear that the deposition of Volker and any future depositions will be held before the Foreign Affairs Committee as well as Oversight and Reform committees.