Maryland Governor Larry Hogan declared a state of emergency and activated the National Guard on Monday in response to riots and looting that escalated in Baltimore on the afternoon of Freddie Gray's funeral, according to a statement from his office.

"I have not made this decision lightly," Hogan said. "The National Guard represents a last resort."

Baltimore Police Commissioner Anthony Batts said in a press conference late Monday evening that the National Guard was already "on the ground here, now, in the city."

Dozens of vehicles and buildings burned across Baltimore, and looters shattered the windows of businesses and made off with armfuls of goods. Some rioters were seen on live television broadcasts poking holes in fire hoses as firefighters tried to extinguish the flames at a CVS store that billowed black smoke. Hogan blamed the violence on "lawless gangs of thugs."

Sounding tired and hoarse, Batts expressed disappointment with the day's events and condemned the violence. "This is not protesting, this is not first amendment rights," he said. "This is just criminal acts."

The National Guard on the scene right now in - Philip Crowther (@PhilipinDC)April 28, 2015

The mayhem continued throughout the evening Monday and spilled over into early Tuesday morning. Police said at around 1am Tuesday that firefighters were being assaulted and that their efforts to put out fires were "disrupted by people with no regard for life." Police said that officers were being deployed to protect the firefighters.

At least 27 people have been arrested. Maryland State Police announced plans to deploy 500 officers to Baltimore and said they will request up to 5,000 more from neighboring states.

"We are deploying resources throughout the city to ensure residents are safe," Baltimore police tweeted around 9:30pm. "Despite our efforts, criminals continue to assault officers."

Baltimore police spokesman Eric Kowalczyk told reporters earlier in the day that some officers sustained broken bones in violent encounters with rioters, and that one officer was "unresponsive." Batts said later Monday night that all the injured officers "are going to be okay."

We are deploying officers with the fire department to ensure fire fighting operations are not disrupted by people w/ no regard for life. - Baltimore Police (@BaltimorePolice)April 28, 2015

Fifteen officers were injured and two hospitalized after a crowd of hundreds of young protesters at a mall turned on riot cops deployed to control the demonstrations and prevent looting.

"This is a group of lawless individuals with no regard for people," Kowalczyk said. "We don't know who is out there. We do [know] they are criminals and have attacked officers without provocation."

Batts blamed the violence on high school students. "This was just youth coming out of the high school and they thought it was cute to throw cinder blocks at the police," he said, urging parents to "take control of your kids."

Several "violent and aggressive" protesters hurled bricks and rocks at officers, while others looted nearby shops and set a police car on fire at North and Pennsylvania Avenues, police said in a series of tweets.

The group is damaging additional police cars in the area. The group is aggressive and violent. We are continuing to deploy resources. - Baltimore Police (@BaltimorePolice)April 27, 2015

Despite having rocks, bricks, and other items thrown at us - officers are using fire extinguishers to put out small fires in the area. - Baltimore Police (@BaltimorePolice)April 27, 2015

An officer came under fire in northwest Baltimore at about 10pm near Virginia Avenue and Reisterstown Road, according to the Baltimore Sun, but nobody was injured and the suspected shooter fled.

Baltimore Mayor Stephanie Rawlings-Blake announced that a citywide curfew will take effect tomorrow from 10pm to 5am, with juveniles ordered off the streets before 9pm. Baltimore city schools have also been ordered closed Tuesday.

The mayor said police will use images and video from social media to prosecute rioters. "We will be holding people accountable," she said. "I'm at a loss for words. It is idiotic to think that by destroying your city, you're going to make life better for anybody."

The White House issued a statement saying new Attorney General Loretta Lynch will "continue to monitor the events in Baltimore," and that the Justice Department is "ready to provide any assistance that might be helpful there."

Protesters shared images on social media of large groups of police assembled on the streets.

A large building - reportedly a senior center that was empty and under construction - caught fire and became engulfed in flames several miles east of where the looting was taking place. A Baltimore Fire Department spokesman initially said the fire was not related to the unrest, but the Associated Press quoted officials saying it was in fact related to the riots.

Bill Murphy, an attorney for the Gray family, told the Washington Post that the family is "devastated" by the violence.

"If this becomes widespread, the mood in Baltimore will shift from what went wrong with the police and Freddie, to how the police are doing a great job at securing this chaos," Gray said. "This won't solve the police problem. This is dangerous to the movement."

Some footage appeared to show an almost carnival atmosphere early in the day, with Michael Jackson music blaring and an individual dancing in the street with a guitar.

The fracas began several hours after the funeral service for Gray, a 25-year-old Baltimore man who died last week after his spine was severed and voice box was crushed while in police custody.

Earlier Monday morning, as thousands thronged to attend Gray's funeral, police announced that a "credible threat" to incite violence has been made by rival gangs against police.

Members from a number of Baltimore gangs including the Crips, Bloods, and Black Guerilla Family "have entered into a partnership to 'take-out' law enforcement officers," according to a police press release.

Police van on fire as well as car on W North - Victoria Bekiempis (@vicbekiempis)April 27, 2015

Police made the announcement as mourners filed into west Baltimore's New Shiloh Baptist Church this morning ahead of the funeral to pay their respects to Gray, who was laid out in an open casket surrounded by flowers. A white pillow was placed near his body with a picture of his face and the words "Peace y'all." Two projector screens nearby flashed the slogans "Black Lives Matter & All Lives Matter."

On the same day, more images and footage continues to emerge of brawls that broke out across Baltimore between police and protesters this weekend, as demonstrations over Gray's death descended into chaos.

Late Saturday, two journalists were swept up in the violence that erupted across the city. The City Paper's photo editor J.M. Giordano posted video to his Instagram account Sunday showing his beating at the hands of police as he tried to cover the protests.

Giordano said he had his "face pretty much smushed down on the ground," after a protester near him allegedly threw a rock at police, prompting officers to tackle him and others to the ground.

"They just swarmed over me," Giordano said, according to the City Paper, which is affiliated with the Baltimore Sun. "I got hit. My head hit the ground. They were hitting me, then someone pulled me out."

Sait Serkan Gurbuz, a photojournalist for Reuters, was arrested in the melee. Police later released the journalist with a citation for "failure to obey orders," which the police later confirmed in a statement would be retracted.

"One journalist (Gurbuz) was released with a criminal citation, which is being recalled," the statement said. "One journalist (Giordano) was released without any charges."

The largely peaceful protests began in the wake of Gray's death on April 19, a week after the 25-year-old sustained a crushed voice box and severed spine in police custody. Over the weekend, demonstrations have given way to rounds of violence and property damage.

At least 34 people, including four juveniles, were arrested citywide Saturday and Sunday, police said, adding that six officers were injured in scuffles.

Baltimore officials sent in 1,200 riot police to control hundreds of protesters Saturday as they marched through the streets chanting and holding banners to call for an end to police brutality and for formal charges to be brought against the six officers involved in Gray's arrest.

A small group of demonstrators later began to throw objects, including water bottles and lit barrels, toward police officers. Some climbed on police cars and smashed windshields and windows of nearby shops.

Despite the frenzy, some protesters continued to call for calm as demonstrations continued Saturday night. Batts praised the actions of those who stood between an angry crowd and a line of riot police backed by mounted officers. Some reportedly pleaded with other demonstrators not to "lose the message."

Earlier, as protests were ramping up Saturday night, Gray's family members called for calm.

"My family wants to say, 'Can you all please, please stop the violence,'" Gray's twin sister, Fredericka, said. "Freddie Gray would not want this."

Ahead of Gray's funeral service Monday, Rawlings-Blake issued a renewed "call for peace."

Thousands of residents attended the service, along with members of Gray's family and relatives of other unarmed black men who have been killed by police in recent months. Among them will be the families of Eric Garner, who died after New York police placed him in an illegal chokehold in July during an arrest over selling loose, untaxed cigarettes.

In Garner's case, a grand jury in December opted not to indict the officer who placed him in the illegal chokehold that killed him, despite the incident being captured on cell phone video. Witnesses also captured Gray's arrest on April 12 on two separate videos, which police said will inform ongoing investigations.

In one of the videos, police can be seen dragging Gray into the back of a police van. One of Gray's legs appears to be limp and lifeless as he is lifted into the wagon. The series of events that follow that moment during the more than 30-minute van ride still remain unclear.

At a press conference Friday, Batts admitted officers committed several breaches of police protocol during the arrest, including failing to fasten Gray securely into a seatbelt in the back of the van and denying him medical attention, despite his numerous pleas for assistance.

"We know he was not buckled in the transportation wagon as he should have been," Batts said. "No excuses for that, period."

When details of Gray's arrest first emerged, police said an officer "made eye contact" with the man before he apparently fled with no immediate provocation. Police have since claimed Gray was taken into custody on drug suspicions, and that he had previously been arrested for alleged drug-related activities.

A lawyer of Gray's family said that that the 25-year-old's spine was "80 percent" severed when he finally arrived at shock trauma. He slipped into a coma and died a week later from his injuries.

All six officers involved in the arrest have been suspended with pay pending the criminal investigation and a separate Department of Justice probe into the incident. Five officers have given statements already, while one has continued to invoke their rights to withhold a statement at this stage, Batts said Friday.