The horrific slow death of a black man at the hands of an impassive white police officer was just the match that lit a building fury.

Black Americans, already reeling from a virus that disproportionately affects them, have engaged in days of protests after an African-American man's death in police custody was caught on tape.

The police statement — which described a suspect "under the influence" who suffered "medical distress", with no mention of the police officer pinning him down — didn't help.

Trump appeared to be the focus of the protesters gathered at the White House, where secret service police donned riot gear to protect the seat of power.

In Minneapolis, roughly 20 per cent of the population is black, but that demographic accounted for 60 per cent of the victims of police shootings between 2009 and 2019.

Of the 1,099 people killed by police last year, almost a quarter were black, despite being only 13 per cent of the population.

Many protesters simply want to see a start to police reform by jailing the four officers involved in the death of George Floyd.

This is a nation where the wealth gap between white and black Americans hasn't changed in 60 years.

It's where the bottom 40 per cent of Americans own just 0.3 per cent of the wealth.

The death of George Floyd also appears to have riled up right-wing militia and "Patriot" forums, which are threatening violence and talking up the prospect of a civil race war known as Boogaloo.

A woman standing on her porch films a Hummer roll down the street, followed by a troop of National Guard and police in military gear.