(CNN) K.T. McFarland, the one-time top deputy to ousted national security adviser Michael Flynn, has accepted the US ambassadorship to Singapore and will likely leave the National Security Council in the coming months, a senior administration official has told CNN.
"She is going to do it, assuming she gets confirmed," the official said.
McFarland intends to continue working at the NSC in the short term, but the official said she is unlikely to stay at the NSC all the way until her confirmation, which could be months away.
"She isn't leaving immediately," the official said.
The official cast the move as a "promotion" for McFarland, but it has been well-known inside the NSC that her hold on the deputy job was tenuous.
CNN reported earlier this month that she had been offered the ambassadorship.
The official said H.R. McMaster, the current national security adviser, has not decided what to do about replacing McFarland, but acknowledged that Dina Powell's role as deputy national security adviser for strategy "will probably expand."
The internal politics of the National Security Council have been in flux since the firing of Flynn in February.
McMaster's power inside the White House has been rising in recent weeks, proven by his orchestration of Steve Bannon's departure from the National Security Council.
McFarland's departure is no different. This means more power for McMaster and people he trusts, such as Powell, who moved over once McMaster took over.
Bloomberg first reported McFarland was going to leave the NSC.