Members of the Maryland National Guard patrol the harbor section of Baltimore, Maryland April 28, 2015. 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. [Photo/Agencies]

BALTIMORE - Baltimore erupted in violence on Monday as hundreds of rioters looted stores, burned buildings and at least 15 police officers were injured following the funeral of a 25-year-old black man who died after suffering a spinal injury in police custody.

The riots broke out blocks from where the funeral of Freddie Gray took place and spread through much of west Baltimore.

It was the most violent protest against police treatment of African Americans since arson and gunfire in Ferguson, Missouri, last year.

A state of emergency was declared by Maryland Governor Larry Hogan, a Republican, who sent in the National Guard, and a curfew was imposed in the majority black city from Tuesday night, with exceptions for work and medical emergencies.

Firefighters battled numerous blazes through Monday night, including one that consumed a church's senior center under construction in East Baltimore. Police said looting, fires and attacks against officers continued overnight.

Looters sacked liquor stores, pharmacies, a shopping mall and a check-cashing store. Rioters smashed car windows outside a major hotel and twice slashed a fire hose while firefighters fought a blaze at a CVS pharmacy that had been looted before it was set on fire.

"All this had to happen, people getting tired of the police killing the young black guys for no reason. ... It is a sad day but it had to happen," said Tony Luster, 40, who was out on the street watching the police line.

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 the incident for possible civil rights violations.

Gray's death reignited a 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.

But after several days of peaceful protests, events turned violent on Monday. Democratic Mayor Stephanie Rawlings-Blake called the looters "thugs" and said they had nothing to do with protests.

Police made at least 27 arrests and Baltimore schools will be shut Tuesday. An Orioles baseball game was canceled and businesses and train stations shut down in the city of 620,000 people 40 miles (64 km) from the nation's capital.