There have been clashes between police and protesters in Minneapolis after the death on Monday of an unarmed black man in police custody in the US city.
Police fired tear gas and protesters threw rocks and sprayed graffiti on police cars.
Video of the death shows George Floyd, 46, groaning “I can’t breathe” as a white policeman kneels on his neck.
Four police officers have been fired, with the mayor saying that being black “should not be a death sentence”.
Mayor Jacob Frey also called on prosecutors to file criminal charges against the policeman who was filmed holding Mr Floyd.
The incident echoes the case of Eric Garner, who was placed in a police chokehold in New York in 2014. His death became a rallying call against police brutality and was a driving force in the Black Lives Matter movement.
What happened at the protests?
They began in the afternoon on Tuesday, when hundreds of people came to the intersection where the incident had taken place on Monday evening.
Organisers tried to keep the protest peaceful and maintain coronavirus social distancing, with demonstrators chanting “I can’t breathe,” and “It could’ve been me”.
Protester Anita Murray told the Washington Post: “It’s scary to come down here in the middle of the pandemic, but how could I stay away?”
A crowd of hundreds later marched to the 3rd Precinct, where the officers involved in the death are thought to have worked.
Squad cars were sprayed with graffiti and protesters threw stones at the police building. Police fired tear gas, flash grenades and foam projectiles.
One protester told CBS: “It’s real ugly. The police have to understand that this is the climate they have created.”
Another said: “I got on my knees and I put up a peace sign and they tear-gassed me.”
Police said one person had suffered non-life-threatening injuries after being shot away from the protest area but gave no further details.
What happened to George Floyd?
Officers responding to reports of the use of counterfeit money had approached Mr Floyd in his vehicle.
According to police he was told to step away from the vehicle and physically resisted officers.
A police statement said: “Officers were able to get the suspect into handcuffs and noted he appeared to be suffering medical distress.”
The video taken at the scene does not show how the confrontation started.
It shows a white officer using his knee to pin Mr Floyd to the ground by the neck.
Mr Floyd groans “please, I can’t breathe” and “don’t kill me” as bystanders urge officers to let him go.
He ceases to move and an ambulance arrives to take him to hospital where he later died.
What was the official response?
Mayor Frey said it was the “right call” to fire the officers.
He said: “Being black in America should not be a death sentence. For five minutes we watched as a white police officer pressed his knee into the neck of a black man. For five minutes. When you hear someone calling for help, you are supposed to help.”
The FBI is investigating the incident and will present its findings to the Minnesota state’s attorney for possible federal charges.
Minnesota Senator Amy Klobuchar urged a thorough outside investigation, saying: “Justice must be served for this man and his family, justice must be served for our community, justice must be served for our country.”
There have been calls from some for the officers to be charged with murder.
The Minnesota police handbook states that officers trained on how to compress the neck without applying direct pressure to the airway can use a knee under its use-of-force policy. This is regarded as a non-deadly-force option.
Photo: One of the protesters in Minneapolis (Getty Images)