U.S. President Donald Trump announced on Twitter on Monday that Mark Esper, his defence secretary, “has been terminated.”
Trump, who thanked Esper for his service, said Christopher Miller, head of the national counterterrorism centre, would serve as replacement.
The move adds more uncertainty to the transition period after the Nov. 3 vote. Trump has refused to concede last week’s election to president-elect Joe Biden, who is set to be inaugurated on Jan. 20.
Esper, 56, was confirmed in the role in July 2019. Previously the secretary of the U.S. army, he had succeeded interim leader Patrick Shanahan as the Pentagon’s top official.
Presidents who win re-election often replace cabinet members, including the secretary of defence, but losing presidents have kept their Pentagon chiefs in place until the inauguration to preserve stability in the name of national security.
Esper’s strained relationship with Trump came close to collapse this past summer during civil unrest that triggered a debate within the administration over the proper role of the military in combating domestic unrest.
Esper’s opposition to using active duty troops to help quell protests in Washington, D.C., infuriated Trump, and led to wide speculation that the defence chief was prepared to quit if faced with such an issue again.
The defence secretary also encouraged a review of the naming of military installations after Confederate leaders, another action Trump expressed his opposition to.
Trump’s first defence secretary, James Mattis, lasted until December 2018 before his departure, which was hastened by disagreements over U.S. policy in Syria.