Another night of unrest has left charred and shattered landscapes in dozens of US cities, as years of festering frustrations over the mistreatment of African Americans at the hands of police boiled over in expressions of rage met with tear gas and rubber bullets.

Cars and businesses were torched, the words “I can’t breathe” were spray-painted all over buildings and a fire in a rubbish bin burned near the gates of the White House, as tens of thousands marched peacefully through city streets to protest against the death of George Floyd.

Mr Floyd, a black man, died on Monday after a white Minneapolis police officer pressed his knee on his neck while restraining him.

His death is one of a litany of racial tragedies that have thrown the US into chaos amid the coronavirus pandemic that has left millions out of work and killed more than 100,000 people, including disproportionate numbers of black people.

Washington protester Olga Hall said: “We’re sick of it. The cops are out of control. They’re wild. There’s just been too many dead boys.”

Meryl Makielski, a protester in Brooklyn, New York, added: “The mistakes that are happening are not mistakes. They’re repeated violent terrorist offences and people need to stop killing black people.”

Some protesters set fire to police cars, threw bottles at officers and looted shops – even as other peaceful demonstrators urged them to stop.

Protest violence
Police officers detain a man outside a vandalised shop in San Francisco’s Union Square (Noah Berger/AP)

In Indianapolis, police are investigating multiple shootings amid the protests, including one that left one person dead – adding to deaths in Detroit and Minneapolis in recent days.

In Minneapolis itself, the city where the protests began, police, state troopers and National Guard members moved in on Saturday soon after an 8pm curfew took effect to break up protests, firing tear gas and rubber bullets to clear streets outside a police station and elsewhere.

At least 13 police officers were injured in Philadelphia when peaceful protests turned violent and at least four police vehicles were set on fire.

In New York City, dangerous confrontations flared repeatedly as officers made arrests and cleared streets. A video showed two NYPD cruisers lurching into a crowd of demonstrators who were pushing a barricade against one of them and pelting it with objects. Several people were knocked to the ground, and it was unclear if anyone was hurt.

Few corners of America are untouched by the protests, with large numbers on the streets from Reno, Fargo and Salt Lake City to Ferguson, Missouri, where Michael Brown was shot and killed by a white police officer in 2014.

Minneapolis Police Death Los Angeles
A police officer prepares to fire rubber bullets during a protest in Los Angeles (Ringo HW Chiu/AP)

Police have arrested at least 1,669 people in 22 cities since Thursday. Nearly a third of those came in Los Angeles, where the governor declared a state of emergency and ordered the National Guard to back up the city’s 10,000 police officers as dozens of fires burned across the city.

US President Donald Trump appeared to cheer on the tougher tactics used against protesters on Saturday night, commending the National Guard deployment in Minneapolis as he declared: “No games!,” and saying police in New York City “must be allowed to do their job!”.

The show of force in Minneapolis came after three days when police largely avoided engaging protesters, and after the state poured in more than 4,000 National Guard troops to the city and said the number would soon rise to nearly 11,000.

Governor Tim Walz, who said local forces had been overwhelmed on Friday, condemned the violence on Saturday as he insisted the protests were no longer about Mr Floyd’s death.

“It is about attacking civil society, instilling fear and disrupting our great cities,” he said.