BALTIMORE (CBSNewYork/AP) — A violent showdown erupted late Monday afternoon, and fires raged in the night, following the death of 25-year-old Freddie Gray in police custody in Baltimore.

Maryland Gov. Larry Hogan earlier Monday evening declared a state of emergency and activated the National Guard in Baltimore.

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“Too many people have spent generations building up this city for it to be destroyed by thugs, who in a very senseless way, are trying to tear down what so many have fought for,” Baltimore Mayor Stephanie Rawlings-Blake said at a news conference Monday evening.

The National Guard has been deployed to assist the local police department, officials said.

“I have not made this decision lightly. The National Guard represents a last resort in order to restore order,” said Maryland Gov. Larry Hogan. “People have the right to protest and express their frustration, but Baltimore City families deserve peace and safety in their communities and these acts of violence and destruction of property cannot and will not be tolerated.”

As CBS2’s Weijia Jiang reported, citywide curfew will be in effect from 10 p.m. to 5 a.m. beginning Tuesday, Rawlings-Blake said. She emphasized that minors 14 and under have a 9 p.m. curfew and minors over 14 have a 10 p.m. curfew at all times.

“It is idiotic to think that by destroying your city, you’re going to make life better for anybody,” she said.

“I’m not going to be as nice as everyone else. I’m simply pissed off,” added Baltimore Councilman Brandon Scott.

U.S. Rep. Elijah Cummings (D-Maryland) also decried the violence to WJZ-TV’s Derek Valcourt outside City Hall in Baltimore.

“We’re better than this, and I know that people are upset, but this is not the way to go about change,” Cummings said. “When we see policemen being hit, stores being broken into and burned, that’s not who we are. I’m asking people to refrain from that. This is our city. After all the cameras are gone, we still have to live here.”

Late Monday night, multiple extra-alarm fires broke out in downtown Baltimore Monday night — at a Southern Baptist Church senior home under construction, an abandoned warehouse, and at two other locations. Baltimore Police Commissioner Anthony W. Batts said it was not clear whether the late-night fires were related to the riots, though fire officials believed that they were.

There were also car fires in the streets late Monday, and police activity persisted.

As CBS2’s Dick Brennan reported, rioters earlier took to the streets Monday afternoon, throwing rocks and bricks at officers and then rampaging up and down blocks – starting at Reisterstown Road and Liberty Heights Avenue near the Mondawmin Mall in Baltimore.

A total of 15 police officers had been injured as of the 8 p.m. hour and two remained hospitalized, Baltimore city officials said. A total of 27 people had been arrested.

A number of the officers reported having broken bones, and one was reported to be unresponsive.

A police shield was also broken during the protest, WJZ-TV, Baltimore reported.

At one point, a group attacked a police patrol car, stomping on it, and smashing windows. A squad car was also set on fire, and protesters stormed into a CVS drugstore at North and Pennsylvania avenues in Baltimore that was later set on fire.

Police said members of the group rioting nearby cut the fire hose while they were attempting to put out the blaze at the drugstore.

Looting reportedly spread to Lexington Market in downtown Baltimore by 8:30 on Monday night. A cell phone store, poultry market, and 7-Eleven near the market were destroyed by looters during the protest on Saturday night.

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City Council President Jack Young urged rioters to “stop the madness.”

“We cannot go back to 1968 where we burned down our own infrastructure and our own neighborhoods. We still have scars from 1968 where we had some burnt out building and businesses did not want to come back to the city of Baltimore. We have to stop the burning down and the breaking in of these stores because in the end it hurts us as a people,” he said. “This is no reason to loot and rob in the city of Baltimore. The whole world is watching us and some people are even calling us animals.”

As WJZ-TV’s Marcus Washington reported, Fredericka Gray — the fraternal twin sister of Freddie Gray – said she thought the violence was a disservice to her brother’s memory.

“I think the violence is wrong, and Freddie Gray wasn’t no person for violence,” she said.” “Freddie Gray wasn’t the type of person to break into no stores or none of that. I don’t like it at all.”

Police said had they received a credible threat Monday morning that there would be violence. But it appeared that as of 5 p.m., police were far from getting the situation under control.

They used tear gas and pepper spray to keep the protesters back.

Reports said some of the rioters came from a nearby high school, and that more of it may have been spread by social media. Some of the rioters appeared to have backpacks strapped to their backs, WJZ-TV reported.

WJZ-TV reporter Christie Ileto reported that some younger children were also seen standing on a knoll throwing rocks and bricks.

At times, the officers in riot gear approached people throwing rocks and other objects, but at other times, they appeared to retreat.

Ileto was hit by pepper spray while covering the protests and rioting. She and her camera crew were not close to the unrest, but she was downwind and was hit with pepper spray in the eyes.

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She reported that an officer helped flush her eyes out.

As CBS2’s Jiang reported, a woman who lives nearby the riots expressed a warning to people watching from across the country.

“This could have been their city. It’s going to be their city, because it’s a reactionary situation,” she said. “People are doing things they’re feeling, and you can only put so much into a pressure cooker before it pops.”

The unrest came on the day that Gray was laid to rest. He died in police custody last week, triggering outrage in the community. The Gray family made an appeal for peace today.

But police made clear on Monday that the people in the streets were not protesters, but lawless criminals.

“We know as this is going on that seven of our officers as of right now have been injured. The exact circumstances that took place that led to their injuries is something that will be determined at a later date. We’re going to go back and do an investigation, and we will find the people responsible and we will put them in jail,” said Baltimore police Capt. Eric Kowalczyk.

CVS reported it had closed some stores due to the riots. The Baltimore Orioles also postponed their planned game against the Chicago White Sox Monday night.

Meanwhile, President Barack Obama late Monday pledged the federal government’s help to respond to the riots.

Obama spoke on Monday with Baltimore Mayor Rawlings-Blake. The White House says the mayor updated Obama on the situation and that Obama told her his administration would provide assistance as needed. Obama’s senior adviser also spoke Monday with Gov. Hogan.

The White House says Obama also discussed the rioting with new Attorney General and former Brooklyn U.S. Attorney Loretta Lynch, who was sworn in hours earlier.

Obama and Lynch met in the Oval Office while the violent scenes of rioting in Baltimore played out on television.

“As our investigative process continues, I strongly urge every member of the Baltimore community to adhere to the principles of nonviolence,” Lynch said in her first statement as Attorney General. “In the days ahead, I intend to work with leaders throughout Baltimore to ensure that we can protect the security and civil rights of all residents. And I will bring the full resources of the Department of Justice to bear in protecting those under threat, investigating wrongdoing, and securing an end to violence.”

Gray died April 19, days after he suffered a severe spinal injury during his encounter with police.

Police said Gray was arrested after he made eye contact with officers and ran away. Officers held him down, handcuffed him and loaded him into the van. While inside, he became irate and leg cuffs were put on him, police have said.

Gray asked for medical help several times, beginning before he was placed in the van. After a 30-minute ride that included three stops, paramedics were called.

Authorities have not explained how or when Gray’s spine was injured. Six officers have been suspended.

Among those who attended Gray’s funeral was Erica Garner, 24 — the daughter of Eric Garner, the man who died in NYPD custody on Staten Island last summer after being put in an apparent chokehold by an officer.

She said she came after seeing video of Gray’s arrest, which she said reminded her of her father’s shouts that he could not breathe when he was being arrested on a city street.

“It’s like there is no accountability, no justice,” she said. “It’s like we’re back in the ’50s, back in the Martin Luther King days. When is our day to be free going to come?”

In December, a grand jury cleared the NYPD officer involved — Daniel Pantaleo — of any wrongdoing, and protests erupted on city streets.

Mayor Bill de Blasio said late Monday that he is not aware of any threats against police in New York City in the wake of violence in Baltimore.

As WCBS 880’s Rich Lamb reported, de Blasio strongly condemned the rioting Monday night.

“Those individuals who committed violence in the last 24 or 48 hours, or any individuals who have assaulted police officers, are denigrating any possible notion of how to improve the situation or bring police and community together or get justice for anyone,” the mayor said.

De Blasio said he was praying for the mayor and police commissioner in Baltimore.

CBS2’s Jiang, who previously worked in Baltimore, said the riots were tragic.

“It’s so hard to watch this. You’re seeing the city burning right now, and I’ll tell you — for as gritty as the city is, it’s filled with so much love, and that’s what we’re seeing. People love their city so much that when they feel like they’re under attack in any way, they respond. And they’re hurting, and they’re passionate,” she said.

But echoing local Baltimore officials Monday night, Jiang said the riots should not be taken in any way as representative of the whole city.

“Even though people are so passionate about this city, this is just a bad group,” Jiang said, adding that the neighborhoods where the riots were occurring are full of boarded-up blocks of homes and a sense of underlying desperation and anger.

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