Top National Security Council official Victoria Coates is being transferred from the White House to the Department of Energy. Coates has bee serving as the deputy assistant to the president and deputy national security adviser for Middle East and North African affairs.

The NSC confirmed her departure in a statement, saying this move has been "in the works for several weeks." Coates will work as a senior adviser to Energy Secretary Dan Brouillette.

"President Donald J. Trump is committed to fostering American energy independence and continuing the positive impact of his pro-growth energy policies on U.S. national security," NSC said in the statement. "To ensure the continued close alignment of energy policy with national security objectives, effective Monday, Deputy National Security Advisor for the Middle East and North Africa Victoria Coates will be joining the Department of Energy as a Senior Advisor to the Secretary. This move has been in the works for several weeks, consistent with the importance the Administration places on energy security."

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National Security Adviser Robert O'Brien said he's "sad" to lose such an important member, but added she'll be an asset to Brouillette.

"She has served the president loyally since the earliest days of the Administration and has played a valued role in the president's Middle East policy," O'Brien said.

Brouillette said in a statement provided by NSC that they're "enthusiastic" about her joining the Energy Department.

A senior administration official said the White House "does not put any stock" in suggestions that Coates is the "anonymous" New York Times op-ed and book author who wrote of an inside resistance movement including many like-minded political appointees who work to thwart President Trump's "more misguided impulses."

"The White House leadership rejects rumors that have circulated recently and does not put any stock in the suggestion that Victoria Coates is the author of Anonymous: A Warning or the related Op-Ed in the New York Times," a senior administration official said. "Dr. Coates' transition to the Department of Energy has been in the works for several weeks and reflects the continued trust and confidence the Administration places in her as she takes on this sensitive role at the Department of Energy, where she will continue working to implement the president's agenda."

Coates and the literary agency of "Anonymous" have strongly denied that she is the author.

It's yet unclear who, if anyone, will replace Coates at NSC.

NSC has seen significant turnover in recent months, and O'Brien is working to whittle down the size of his staff.

— Kathryn Watson and Kristin Brown contributed to this report