Violence has erupted in cities across the US on the sixth night of protests sparked by the death in police custody of African-American George Floyd.
Curfews have been imposed in nearly 40 cities, but people have largely ignored them, leading to tense stand-offs.
Riot police clashed with protesters in New York, Chicago, Philadelphia and Los Angeles, firing tear gas and pepper bullets to try to disperse the crowds.
Police vehicles were set on fire and shops were looted in several cities.
The National Guard – the US reserve military force for domestic emergencies – said on Sunday that 5,000 of its personnel had been activated in 15 states and Washington, DC, where crowds once again gathered near the White House, this time lighting fires and throwing stones at riot officers.
“State and local law enforcement agencies remain responsible for security,” the National Guard added.
Police in Washington DC have fired tear gas at demonstrators who set fire to properties near the White House. They include a historic church, St John’s Episcopal Church, known as the church of the presidents, near the White House.
It has emerged that in Friday night’s unrest, President Donald Trump was briefly taken by the secret service into an underground bunker at the White House, for his safety.
The US is witnessing the most widespread racial turbulence and civil unrest since the violent backlash to the assassination of Martin Luther King in 1968, says the BBC’s Nick Bryant.
More than 75 cities have seen protests, with streets only days ago deserted because of coronavirus, thronged with demonstrators marching shoulder to shoulder.
The Floyd case has reignited anger over police killings of black Americans. For many, the outrage also reflects years of frustration over socio-economic inequality and segregation, not least in Minneapolis itself, where George Floyd died.
What’s the latest on the protests?
There were many instances of police vehicles being vandalised and set alight on Sunday. Riot officers continued to respond with tear gas and flash grenades.
In Philadelphia, local TV stations showed people smashing police cars and looting at least one store.
Mr Trump tweeted: “Law & Order in Philadelphia, NOW! They are looting stores. Call in our great National Guard.”
Looting was also reported in Santa Monica, California.
At least 4,400 people have been arrested over several days of protests, according to a tally compiled by the Associated Press news agency. Arrests have been made over a range of offences, from looting and blocking motorways to breaking curfew.
In Denver, thousands of people protested peacefully in Colorado State Capitol by lying face down with their hands behind their backs and chanting: “I can’t breathe” – a reference to the circumstances of Mr Floyd’s death.
Large-scale protests also took place in Atlanta, Boston, Miami and Oklahoma City.
There were also several reported incidents of riot police responding disproportionately to the demonstrators. In Atlanta, Georgia, two officers were sacked on Sunday for using excessive force – including firing a taser – on two young college students.
What happened to George Floyd?
On the evening of Monday 25 May, police received a phone call from a neighbourhood grocery store alleging that George Floyd had paid with a counterfeit $20 note.
Officers were attempting to put him in a police vehicle when he dropped to the ground, telling them he was claustrophobic.
According to police, he physically resisted officers and was handcuffed. Video of the incident does not show how the confrontation started.
With Mr Chauvin’s knee on his neck, Mr Floyd can be heard saying “please, I can’t breathe” and “don’t kill me”.
According to a preliminary autopsy by the county medical examiner, the police officer had his knee on Mr Floyd’s neck for eight minutes and 46 seconds – almost three minutes of which was after Mr Floyd became non-responsive.
Nearly two minutes before Mr Chauvin removed his knee the other officers checked Mr Floyd’s right wrist for a pulse and were unable to find one. He was taken to hospital and pronounced dead around an hour later.
Derek Chauvin, 44, was charged with third degree murder and was due to appear in court later on Monday, but his appearance has now been pushed back to 8 June.
It follows the high-profile cases of Michael Brown in Ferguson, Eric Garner in New York and others that have driven the Black Lives Matter movement.