United States Defence Secretary Jim Mattis will be retiring at the end of February, President Donald trump announced on Twitter Thursday evening. 

A seasoned campaign veteran at age 36, Ayers is emerging as a leading contender to replace White House chief of staff John Kelly, whose departure has long been the subject of speculation.

With whispers of a staffing purge permeating the West Wing, the White House pushed back Friday and insisted that reports of tumult and imminent departures are overblown. Chief of staff John Kelly, himself the subject of rumors that his days are numbered, assured a group of staffers their jobs were safe, at least for now.