Men shout "Freddie G" as they protest against the death of 25-year-old black man Freddie Gray who died in police custody in Baltimore, Maryland April 28, 2015. Baltimore's mayor came under criticism on Tuesday for a slow police response to some of the worst urban violence in the United States in years in which shops were looted, buildings burned to the ground and 20 officers were injured. [Photo/Agencies]

Bars and restaurants were shutting down early since they did not expect clients due to the 10 pm curfew for all adults, which will last the rest of the week.

"We have no exceptions other than for medical or coming and going from work. We will be stopping people who are out after curfew. We are taking that seriously. We don't want to engage in any forceful action," Police Commissioner Anthony Batts told reporters.

Peaceful protesters marched through some Baltimore streets on Tuesday, but there was no sign of the rock- and brick-throwing that set off a night of looting and arson that burned 19 buildings and left one person in critical condition.

"They tore the city down last night, and today we're trying to rebuild it again," said Perry Hopkins, who formed a line of men from the community separating police from the crowd in the afternoon.

Volunteers armed with brooms cleaned up debris from burned out and looted buildings in the city of 620,000 people, where schools, many businesses and some government offices closed until security improved.

The security crisis disrupted the city's daily routines. In a rare move, the Major League Baseball game between the Baltimore Orioles and Chicago White Sox will be played as scheduled Wednesday but closed to the public.

Acrid smoke hung over the streets and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives said it was sending two teams to Baltimore to investigate the multiple blazes on Monday night.

Gray was arrested on April 12 while running from officers. He was taken to the police station in a van, with no seat restraint and suffered a spinal injury.

Six officers have been suspended, and the US Justice Department is investigating possible civil rights violations.