Gen Brown had been visiting troops at the southern US border on Friday, roughly two hours before Trump’s post announcing his departure.

Rumours had been swirling this week that the president would remove the commander, whose term was set to expire in 2027.

Gen Brown made headlines in 2020 when he spoke out about race following the death of George Floyd.

He posted a video message to the US Air Force describing the pressures he had felt as one of the few black men in his unit, including being questioned about his credentials.

In 2022, while chief of staff of the air force, Gen Brown co-signed a memo setting out diversity goals to boost the proportion of minority officer applicants while adjusting lower the rate of white candidates, according to the Air Force Times, external.

Colin Powell was the first black chairman of the joint chiefs of staff, serving from 1989-93.

One of Trump’s first acts after being sworn in last month was to fire the first female commandant of the Coast Guard, citing “excessive focus” on diversity.