One person was shot and gravely wounded on Wednesday in a second night of unrest in Charlotte, North Carolina.
North Carolina's governor later declared a state of emergency amid the disturbances and said the National Guard and state Highway Patrol troopers would be sent in to help police in Charlotte restore and maintain order.
The latest trouble began with a peaceful rally that turned violent after several hundred chanting demonstrators marched through the town with brief stops at a black church, police headquarters and a large entertainment venue called the EpiCentre.
As they approached downtown, Charlotte's central intersection, protesters confronted a column of patrol cars and officers in front of the Omni Charlotte Hotel and began to surround groups of police and their vehicles.
Police then unleashed volleys of rubber bullets, pepper spray, tear gas and flash-bang grenades to disperse the protesters, who began hurling fireworks and debris at officers outside the hotel.
The confrontation grew more intense as a phalanx of helmeted police carrying shields advanced down a street, pushing back a crowd of demonstrators who scurried for cover as officers fired more tear gas.
Black activists and pastors called for an economic boycott of the city, and the American Civil Liberties Union urged police to release body and dashboard camera footage of the incident.