By Arun Kumar

Washington, April 28 (IANS): Baltimore City, just 64 km northeast of the American capital, erupted into chaos and violence as protesters mourning the death nine days ago of yet another black man in police custody clashed with police.

Maryland Governor Larry Hogan declared a state of emergency Monday and activated the National Guard. The mayor of Baltimore said every possible resource was being deployed to "gain control of this situation."

Clashes left at least 15 police officers injured, according to media reports. With the city imposing a mandatory curfew from 10 p.m. to 5 a.m. daily, for a week starting Tuesday Baltimore City Public Schools will be closed Tuesday.

Monday's violence came the same day as the funeral of Freddie Gray, 25, who was arrested on April 12 and died one week later from a fatal spinal cord injury.

Six officers have been suspended, but investigators say they still don't know how it happened, according to CBS News.

Time magazine recently listed 14 major instances of a white cop shooting dead a black person from 17-yearold Trayvon Martin being fatally shot on Feb 26, 2012 in Sanford, Florida to the April 4 shooting of Walter Scott in North Charleston, South Carolina.

According to a report 154 persons have died at the hands of law enforcement officers since January with 37 killed in April alone.

"What we see tonight that is going on in our city is very disturbing," Baltimore Mayor Stephanie Rawlings-Blake told reporters Monday.

Rawlings-Blake also promised to hold those responsible for the violence accountable.

More than two dozen people have already been arrested, CNN reported citing Col. Darryl D. DeSousa with the Baltimore Police Department.

DeSousa described the violence as "unprecedented." A Video showed police in riot gear taking cover behind an armoured vehicle, as protesters pelted them with rocks.

The Baltimore Police Department said it had heard reports of protesters setting small items on fire, and footage showed a cruiser in flames.

Video also showed people looting local stores, and an area pharmacy was set on fire after it was ransacked. Thick dark smoke filled the streets, CNN said.

Earlier in the day, the Baltimore Police Department said it had received a "credible threat" that gangs were teaming up to "take out" officers.

Up to 5,000 law enforcement officials will be requested from the mid-Atlantic region to help quell the violence in Baltimore, Col. William Pallozzi of the Maryland State Police said at a press conference late Monday.

Over the weekend, a few protesters vandalized police cars, threw objects at officers, cursed at them and scuffled with them.

Some others smashed squad cars with garbage cans, climbed on top of them and stomped on them, CNN video showed.