The top-ranking Democrat in the US government said it appears outgoing US President Donald Trump is "intent on using his final days in office to sow chaos", after he abruptly fired his Defence Secretary on Tuesday (NZ time).
"Mark Esper has been terminated," Trump tweeted, appointing Christopher Miller, director of the National Counterterrorism Center, as Acting Secretary "effective immediately".
Esper and Trump clashed on a number of issues, most notably Trump's call for troops to be deployed on US soil to suppress Black Lives Matter protests earlier this year.
"The abrupt firing of Secretary Esper is disturbing evidence that President Trump is intent on using his final days in office to sow chaos in our American democracy and around the world," said Nancy Pelosi, Speaker of the House of Representatives and third in line to the presidency, behind Trump and Vice President Mike Pence.
"Continuity and stability are always important during a presidential transition; they are absolutely imperative at this moment, as this historically erratic administration prepares for its departure.
"It is concerning that reports show that this firing was an act of retribution by the President, allegedly for Secretary Esper's refusal to send active-duty military troops to crack down on peaceful demonstrations against police brutality. Most disturbingly, however, the timing of this dismissal raises serious questions about Trump’s planned actions for the final days of his administration.
"Again and again, Trump's recklessness endangers our national security."
Esper only found out about his dismissal shortly before Trump told the world via Twitter, an anonymous official told Reuters. Miller was seen arriving at the Pentagon within an hour, before the Pentagon had even confirmed Esper was no longer in charge.
Adam Smith, a Democrat who leads the House Armed Services Committee, called the firing "childish" and reckless.
"Dismissing politically appointed national security leaders during a transition is a destabilising move that will only embolden our adversaries and put our country at greater risk."
Esper publicly disagreed with Trump over how to handle protests in the wake of the death of George Floyd in Minneapolis.
"The option to use active duty forces in a law enforcement role should only be used as a matter of last resort, and only in the most urgent and dire of situations," he said at the time. "We are not in one of those situations now."
Esper appeared with Trump during the infamous photo session outside Washington DC's St John's Episcopal Church during the protests, but later said he was not aware protesters had been removed by force beforehand.
"I was not aware of the law enforcement plans for the park. I was not briefed on them, nor should I expect to be."
Trump's relationship with Esper's predecessor Jim Mattis was also rocky. Mattis, who served for two years, in June said Trump was the "first president in my lifetime who does not try to unite the American people - does not even pretend to try".
Since losing the election last week, Trump has also fired the administrator of the National Nuclear Security Administration, the deputy administrator of the US Agency for International Development and the chairman of the Federal Energy Regulatory Commission.
The New York Times said the firings suggest Trump "intends to continue to defy the usual post-election comity to muscle through his policies and appointees for as long as he can".
Joe Biden will be sworn in as US President on January 20, with Trump remaining in charge until then.
