Washington (CNN) Nadia Schadlow, the US deputy national security adviser for strategy, has resigned and will leave her position at the end of the month, multiple administration officials told CNN.

Schadlow is the third senior national security official to resign or be pushed out in the wake of national security adviser John Bolton's entrée to the White House. She submitted her resignation on Tuesday, according to a copy of her resignation letter obtained by CNN, and a senior White House official said she will remain in her role until April 27 to assist with the transition.

"The administration thanks Dr. Schadlow for her service and leadership in crafting the President's 'America First' national security strategy. The strategy has set a strong foundation going forward for protecting the homeland, promoting American prosperity, preserving peace through strength and advancing American influence. We wish Nadia and her family the best," White House spokesman Raj Shah said in a statement to CNN.

Sources close to the National Security Council have for weeks expected that Schadlow, who was a close adviser to Lt. Gen. H.R. McMaster, would resign or be pushed out after President Donald Trump announced he was replacing McMaster with Bolton. A senior White House official said Schadlow spoke with Bolton on Tuesday and submitted her resignation "to allow him to build his own NSC leadership team." Schadlow offered to remain on board for several weeks to ensure a smooth hand off, the official said.

Bolton has yet to announce any new senior staff who will join him at the National Security Council, though a White House official said Bolton has begun assembling a team.

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