US President Donald Trump has fired Mark Esper as the defence secretary and announced an acting replacement, making the announcement over Twitter.
The step was not entirely unexpected and comes in the wake of Trump losing the presidential election, although he continues to contest the results.
There have been simmering tensions between the two since the summer, with Esper having publicly distanced himself from Trump over the tough crackdown by the federal government targetting protests against racism and police violence.
The president had considered using a law from 1807 to deploy military forces against the demonstrations and Esper, a former soldier, came out strongly against the idea.
Esper has also effectively banned the display of symbols of the Confederate rebels during the Civil War within the military and has reportedly also been working to change the names of bases named for generals who fought for the slave-owning South.
“Mark Esper has been terminated. I would like to thank him for his service,” Trump said.
He announced that Christopher Miller, the current director of the National Counterterrorism Center, would take over in an acting capacity.
Last week, NBC News reported that Esper had prepared a resignation letter, though the Pentagon had denied that he was quitting.
Trump’s first secretary of defence, James Mattis, resigned in 2018 in protest over the president’s policy in Syria, and later came out more clearly against Trump’s general attitudes towards allies.
The White House in the last four years has been rife with chaos, including high-turnover and sudden terminations over Twitter.