BALTIMORE (Reuters) - Baltimore residents on Tuesday began to clear the wreckage of rioting and fires that erupted after the funeral of a 25-year-old black man who died in police custody, while the city's mayor defended local law enforcement's light initial response.

Acrid smoke hung over streets where violence broke out just blocks from Freddie Gray's funeral and spread through much of the poor West Baltimore neighborhood. Nineteen buildings and 144 vehicles were set on fire, and 202 people were arrested, according to the mayor's office.

Police said 15 officers were injured, six seriously, in Monday's unrest, which spread throughout the city as police initially looked on but did not interfere as rioters torched vehicles and later businesses.

Looters had ransacked stores, pharmacies and a shopping mall and clashed with police in riot gear in the most violent unrest in the United States since Ferguson, Missouri, was torn by gunshots and arson in late 2014.

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

A man cleans up Pennsylvania avenue as Maryland State police stand guard Monday in Baltimore, Maryla …

"It's a very delicate balancing act, when we have to make sure that we're managing but not increasing and escalating the problem," Baltimore Mayor Stephanie Rawlings-Blake told reporters on Tuesday.

Police in Ferguson came under intense criticism last year for quickly adopting a militarized posture, using armored vehicles, showing heavy weapons and deploying tear gas in a forceful response that some said escalated tensions in the St. Louis suburb.

New York's police department took a more flexible approach in protests later in the year, monitoring marches that crisscrossed the city but largely averting the kind of violence seen in Ferguson and Baltimore.

For nearly a week after Gray died from a spinal injury on April 19, protests in Baltimore had been peaceful.