Rioting broke out Monday in Baltimore, a city just miles from the US capital, shortly after the funeral of a black man who died last week of injuries suffered in police custody.
Several police officers were injured, police cars were stoned and torched, stores were looted, most of which was reported live by TV news crews camped out in the city for past several days.
Violence and looting continued for several hours before police and firefighters moved in to try and take back control of the streets and put out fires that had raged for a while.
Looters were seen arriving in cars with bags to carry away stolen goods. Targets included a major pharmacy, liquor stores, groceries and a cheque payment facility.
Local authorities imposed a state of emergency in the city, and a night-time curfew from 10pm to 5am from Tuesday, with an earlier cut-off for school-going children.
President Barack Obama reviewed the situation with his new African American attorney general, Loretta Lynch, who took oath of office earlier in the day, at a pre-arranged meeting.
An angry Baltimore mayor Stephanie Rawlings-Blake Bowles, an African American, called rioters “thugs” with “idiotic” motivations.
Rioters included a large number of school-age children, who may have even started the violence targeting a mall across the road from their school in a pre-arranged action.
Baltimore is a black-majority city with black mayor and police commissioner, who have struggled to change a police department known for aggressive behaviour against black men.
Protests that turned into rioting on Monday started last week after the death of Freddie Gray, 25, of severed spinal cord, an injury he suffered in custody on April 12.
Six police officers have been suspended but protests have continued, despite appeals from local authorities for calm. Baltimore is the new Ferguson and New York City.
Ferguson in Missouri state was rocked for months in 2014 by protests over the killing of a black teen by a white police officer who was later cleared of any wrongdoing by a grand jury.
A group of white police officers were similarly let off in New York city in connection with the case of black man who died gasping for breath as officers wrestled him down.
An elderly Indian visiting his son in Alabama was partly paralyzed after being slammed to the ground by a white police officer responding to a 911 call about a “skinny black guy”.
Watch: Looters target stores amidst protests in Baltimore
President Obama has set up a task force to recommend ways to improve police relations with ethnic minorities, which, according to a report, were shockingly bad in Ferguson.
Circumstances of Gray’s arrest remain clear. According to the police when he was confronted by officers at around 8:30am, he bolted. He was arrested after a chase.
“They had him in a crab-like position, where his legs were bent back and his arms,” an unidentified witness told a local TV stations. “He was handcuffed, and at that point, they had knees in his back and his head.”.
(With inputs from AFP)