Baltimore residents on Tuesday began cleaning up the wreckage from rioting and fires that erupted after the funeral of a 25-year-old black man who died after suffering a spinal injury in police custody.

Acrid smoke hung over streets where fire crews raced to contain damage from violence that broke out just blocks from the funeral of Freddie Gray and spread through much of West Baltimore.

The unrest - which saw looters ransack stores, pharmacies and a shopping mall and clash with police in riot gear - was the most violent in the US since Ferguson, Missouri, was torn by gunshots and arson late last year.

Volunteers swept up charred debris and broken glass in front of a CVS pharmacy in a poor west Baltimore neighborhood as dozens of police officers in riot gear stood by while firefighters worked to damp down the embers.

"I'm just here to help out, man. It's the city I'm from," said Shaun Boyd, 30, as he swept up broken glass, part of a group of people using donated brooms and scoops in the cleanup effort.

Police said 15 officers were injured, six seriously, in Monday's unrest.

Gray's death gave new energy to the public outcry over police treatment of African Americans that flared last year after police killings of unarmed black men in Ferguson, New York City and elsewhere.

The violence appeared to catch city officials and community leaders off-guard after a week of mostly peaceful protests following Gray's death on April 19.

Maryland Governor Larry Hogan, a Republican, declared a state of emergency on Monday and the National Guard was arriving in the city. A one-week curfew was also imposed in the largely black city starting Tuesday night, with exceptions for work and medical emergencies.

Baltimore-based fund manager T. Rowe Price Group Inc said it would close its downtown office on Tuesday while Legg Mason, also headquartered downtown, said its office would be open but it was encouraging employees to work from home.

Answering criticism of not responding quickly enough to Monday's events, Mayor Stephanie Rawlings-Blake told CNN: "This was an incident that sparked this afternoon ... I think it would have been inappropriate to bring in the National Guard when we had it under control."

On Monday, youths threw rocks and bricks at police. Rioters smashed car windows outside a major hotel and twice slashed a fire hose while firefighters fought a blaze at the CVS that had been looted before it was set on fire.

Police made at least 27 arrests and Baltimore schools were closed on Tuesday in the city of 620,000 people, 40 miles from the nation's capital.

"When you see the destruction you've also got to realize there's pain, there's pain behind a lot of this," said U.S. Representative Elijah Cummings, a Democrat who represents the region hit by the rioting.

Speaking to reporters as police helicopters hovered overhead, Cummings called on Rawlings-Blake to order a new review of police practices in the city.

The mayor, he said, should "assure us that the police department be looked at from top to bottom, everything from parking tickets straight up to indictments for murder."

CAUGHT OFF-GUARD

Gray was arrested on April 12 when running from officers. He was transported to the police station in a van, with no seat restraint and suffered the spinal injury that led to his death a week later. A lawyer for Gray's family says his spine was 80 percent severed at the neck while in custody.

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

Much of Monday's rioting occurred in a neighborhood where more than a third of families live in poverty, parts of which had not been rebuilt since the 1968 rioting that swept across the United States after the assassination of civil rights leader Martin Luther King Jr.

Deadly confrontations between mostly white U.S. police and black men, and the subsequent unrest, will be among the challenges facing U.S. Attorney General Loretta Lynch, who was sworn in on Monday and condemned the "senseless acts of violence."

Riots over police brutality and race issues have gripped U.S. cities before.

In the 1992 Los Angeles riots, more than 50 people were killed in violence set off by the acquittal of four police officers who beat black motorist Rodney King. Dozens died in 1968 riots, including several in Baltimore.

As he surveyed the wreckage of the destroyed drug store, 36-year-old longshoreman Dave Johnson called the rioting "ridiculous."

"It's like setting a fire in your own house and then sleeping in it," Johnson said. "It shows parents are not accountable with control of their kids."-Reuters