Police stand guard outside the White House as people gather to protest the death of George Floyd in Washington, DC.
MINNEAPOLIS - Authorities imposed curfews in the capital Washington and other major US cities to prevent fresh rioting after anti-racism protesters again took to the streets to voice their fury at police brutality.
As the Trump administration branded instigators of five nights of rioting domestic terrorists, there were more confrontations between protestors and police and fresh outbreaks of looting.
Local leaders appealed to citizens to give constructive outlet to their rage over the death of an unarmed black man, while night-time curfews were imposed in cities such as Washington, Los Angeles, Houston and Minneapolis, which has been the epicentre of unrest.
IN PICTURES: Protests flare around US over George Floyd killing
The most closely-watched protest was outside the state capitol in Minneapolis' twin city of St. Paul where several thousand people gathered before marching down a highway.
Hundreds of police and National Guard troops were deployed ahead of the protest.
There were other large-scale protests in cities such as New York, Miami and Washington where riot police lined up outside the White House as the crowds gathered at a nearby park.
Washington's mayor issued a curfew order from 11pm until 6am as a report in the New York Times said that President Donald Trump had been rushed by Secret Service agents into an underground bunker at the White House on Friday night during another protest.
While there was no immediate repeat of the large-scale violence that has rocked cities in recent days, looters ransacked stores in a neighbourhood of Philadelphia.
Officials in LA -- a city scarred by riots over the police beating of Rodney King nearly three decades ago -- imposed a curfew from 4pm Sunday until dawn.
The shocking videotaped death last Monday of an unarmed black man, George Floyd, at the hands of police in Minneapolis ignited the nationwide wave of outrage over law enforcement's repeated use of lethal force against unarmed African Americans.
Floyd stopped breathing after Minneapolis police officer Derek Chauvin knelt on his neck for nearly nine minutes.
Chauvin has been charged with third-degree murder and is due to make his first appearance in court on Monday; three other officers with him have been fired but for now face no charges.