Maryland Gov. Larry Hogan declared a state of emergency and activated the National Guard after riots erupted in Baltimore.
Up to 5,000 law enforcement officials will be requested from the mid-Atlantic region to help quell violence in Baltimore, a Maryland State Police official said.
Baltimore Mayor Stephanie Rawlings-Blake said the city will impose a mandatory curfew from 10 p.m. to 5 a.m. daily, starting on Tuesday and effective for one week.
Fifteen police officers have been injured during riots and two remained hospitalized, police said. More than two dozen people have been arrested.
Seven Baltimore police officers have suffered major injuries in street clashes, a police spokesman said.
One officer was knocked unconscious and others had broken bones, Capt. Eric Kowalczyk said. Video showed a police car burning and a pharmacy damaged.
The unrest came the same day as the funeral in West Baltimore for Freddie Gray, who died while in police custody.