Donald Trump has ordered the FBI and the Department of Justice to “expedite” the investigation into the death of a black man who died after being pinned down by police.
George Floyd died after a white police officer kneeled on his neck, despite him saying he could not breathe, in the US state of Minnesota.
It comes as the mayor of Minneapolis, the city in which the incident happened, called for criminal charges against the officer.
The US President said on Wednesday the Justice Department and FBI were probing the case, and are already “well into” their investigation.
"At my request, the FBI and the Department of Justice are already well into an investigation as to the very sad and tragic death in Minnesota of George Floyd," Mr Trump said on Twitter.
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"I have asked for this investigation to be expedited and greatly appreciate all of the work done by local law enforcement," he said.
"My heart goes out to George’s family and friends. Justice will be served!"
Footage of the of the death shared on social media showed Mr Floyd, 46, saying "I can't breathe" and "don't kill me" as a policeman kneeled on his neck.
Four police officers were fired, with the mayor saying that being black "should not be a death sentence”.
Based on the video, mayor Jacob Frey said the officer should be charged.
"I've wrestled with, more than anything else over the last 36 hours, one fundamental question: Why is the man who killed George Floyd not in jail?" mayor Frey.
He later added: "I saw no threat. I saw nothing that would signal that this kind of force was necessary.
The incident echoed the case of Eric Garner, who died after being placed in a police chokehold in New York in 2014.
His death became a rallying call against police brutality and a driving force for the Black Lives Matter movement.
Thousands of people flooded the streets to demand justice over Mr Floyd’s death.
Hours after the officers’ dismissals were announced, thousands of protesters filled the streets close to the scene where the incident took place on Monday.
