Baltimore declares state of emergency amid protests

The governor of Maryland has declared a state of emergency and activated the National Guard to help with the violence and rioting in Baltimore. Gov. Larry Hogan signed the order Monday night at the request of the city.

A CVS drugstore and a Baltimore MTA police car were set on fire Monday afternoon amid civil protests in the aftermath of the death of Freddie Gray.

"We are working with our partners in the Baltimore City Fire Dept while they put the fire out at the business - Pennsylvania /North Ave," The Baltimore Police Department said via Twitter.

Gray, who was 25 years old, died after suffering serious spinal injuries while in police custody. He died April 19, days after his encounter with police. Earlier on Monday, the 2,500-capacity New Shiloh Baptist church was filled with mourners, many of whom filed past Gray's casket before the service began.

At least seven police officers suffered injuries after a clash with a large group of protesters, officials said. The White House said it was monitoring the situation.

"I strongly condemn the actions of the offenders who are engaged in direct attacks against innocent civilians, businesses and law enforcement officers," Hogan said in statement via Twitter.

A number of business were looted, including a CVS store that was later set ablaze. Other smaller businesses were also looted, including a deli, a check-cashing storefront and a liquor store.

"Due to protest activity occurring near our store on the 2500 block of Pennsylvania Ave., we closed this location earlier this afternoon out of an abundance of caution. No customers or employees were in the store when looters broke into it," a CVS spokesperson told CNBC.

Captain Eric Kowalczyk of the Baltimore Police said the department would take all appropriate methods to keep the community safe, including the use of tear gas and pepper balls, if necessary.

The University of Maryland Baltimore warned residents to stay indoors as tension mounted on streets.

University of Maryland's tweet.

Orioles tweet.

Hogan tweet.

—CNBC's Ryan Ruggiero and The Associated Press contributed to the report.