At least five US police officers have been hit by gunfire during violent protests over the death of a black man in police custody, hours after President Donald Trump vowed to use the military to halt the unrest.
Trump deepened outrage on Monday by posing at a church clutching a bible after law enforcement officers used teargas and rubber bullets to clear the way for him to walk there after he made his remarks in the White House Rose Garden.
Demonstrators set fire to a strip mall in Los Angeles, looted stores in New York City and clashed with police in St Louis, Missouri, where four officers were hit by gunfire and taken to hospital with non-life-threatening injuries.
"Officers are still taking gunfire downtown & we will share more info as it available," St Louis Police said on Twitter.
A police officer was also shot during protests in the Las Vegas Strip area, AP news agency said, quoting police. Another officer was "involved in a shooting" in the same area, the agency said without giving details.
Trump has condemned the killing of George Floyd, a 46-year-old African American who died after a white policeman pinned his neck under a knee for nearly nine minutes in Minneapolis on May 25, and has promised justice.
Derek Chauvin, the 44-year-old Minneapolis police officer who kneeled on Floyd, was arrested on third-degree murder and second-degree manslaughter charges. Three other officers involved in the arrest have not been charged.
With anti-police brutality marches and rallies having turned violent after dark each day in the past week, Trump said rightful protests could not be drowned out by an "angry mob".
"Mayors and governors must establish an overwhelming law enforcement presence until the violence has been quelled," Trump said.
"If a city or state refuses to take the actions that are necessary to defend the life and property of their residents, then I will deploy the United States military and quickly solve the problem for them."
The National Guard deployed in 23 states and Washington, D.C.
Following his address, Trump walked through an area that had been cleared by police to nearby St. John's Episcopal Church, where he posed for pictures, holding up a bible.
The presiding bishop of the Episcopal Church diocese in Washington D.C., Michael Curry, was among those who criticised Trump's use of the historic church for a photo opportunity.
"In so doing, he used a church building and the Holy Bible for partisan political purposes," he said on Twitter. The church suffered minor fire damage during protests on Monday night.
The White House said it was clearing the area before a curfew.
Television images showed crowds smashing windows and looting luxury stores along Fifth Avenue in New York's Manhattan before the city's 11pm curfew.
Two police officers were struck by a car at a demonstration in Buffalo, New York, on Monday night. Officials said the driver and passengers were believed to be in custody.
In Hollywood, dozens of people were shown in television images looting a drug store. Windows were shattered at a nearby Starbucks and two restaurants.
A second autopsy ordered by Floyd's family and released on Monday found his death was homicide by "mechanical asphyxiation," or physical force that interfered with his oxygen supply. The report says three officers contributed to his death.
The Hennepin County Medical Examiner later released autopsy findings that also called Floyd's death homicide by asphyxiation. The county report said Floyd suffered cardiopulmonary arrest while being restrained by police and that he had arteriosclerotic and hypertensive heart disease, fentanyl intoxication and recent methamphetamine use.
Australian Associated Press