White House Deputy National Security Adviser Mira Ricardel has left her post, following a high-profile row with US First Lady Melania Trump.
A White House spokeswoman said Mrs Ricardel “departs the White House to transition to a new role within the administration”. She did not elaborate.
Mrs Trump this week said that Mrs Ricardel “no longer deserves the honour of serving in this White House”.
The two reportedly feuded during a tour of Africa in October.
In a statement on Wednesday, White House spokeswoman Sarah Sanders said that Mrs Ricardel “will continue to support the president”.
According to US media reports earlier this week, Mrs Trump and Mrs Ricardel quarrelled over seating arrangements on her plane.
During her trip there, Mrs Trump told ABC in a rare interview that there were people in the White House who she does not trust.
She said she gave the president “my honest advice and honest opinions and then he does what he wants to do”.
The Wall Street Journal had earlier reported that Mrs Trump’s team believed Mrs Ricardel was behind some of the “negative stories” about Mrs Trump and her staff.
The newspaper also reported that she repeatedly clashed with US Secretary of Defense James Mattis over “staffing decisions and policy differences”.
Mrs Ricardel was hired away from the Department of Commerce by National Security Advisor John Bolton, and has decades of experience working in the US government.
She had earlier worked in the defence department under former President George W Bush as well as under Republican Senator Bob Dole when he served as the Senate Majority Leader.