A protester yells at police shortly before shots were fired in Ferguson, Missouri, Aug. 9, 2015. St. Louis County declared a state of emergency Monday after officials charged a man with shooting at police. Reuters

An 18-year-old from St. Louis was charged Monday with multiple criminal counts for his role in a shooting during protests in Ferguson, Missouri, Sunday night, exactly one year after the death of Michael Brown. St. Louis County then declared a state of emergency Monday in response to the violence, during which Tyrone Harris Jr., was shot and critically injured by police. Harris, who faces charges that include four counts of first degree assault on law enforcement in the first degree, was being held on $250,000 bail after undergoing surgery at around 3 a.m. Monday, and faces a $250,000 bail, according to the St. Louis Post-Dispatch.

Harris allegedly used a stolen 9mm Sig Sauer semiautomatic pistol to fire gunshots at four St. Louis County plainclothes detectives riding in a vehicle. The detectives then returned fire before critically wounding Harris amid demonstrations commemorating the anniversary of the death of Brown, an unarmed black 18-year-old who was shot and killed by now-former Ferguson police officer Darren Wilson.

Harris was charged with four counts of first-degree assaults on law enforcement, five counts of armed criminal action, and one count of discharging or shooting a firearm at a motor vehicle. Harris' father, Tyrone Harris Sr., said that his son and Brown "were real close" but that he believed his son was unarmed and that "there's a lot more to this than what's being said," according to the Washington Post.

In addition to Harris, two young men, one 17 and and one 19, were shot around 2 a.m. Monday nearby where Brown was shot. The victims told police that they were walking on the sidewalk when a man in a red hooded sweatshirt began shooting at them from the rear passenger side of the window, according to the Washington Post.

The people doing the shooting "were criminals," St. Louis County Police Chief Jon Belmar said, reported the Saint Louis Post-Dispatch. "They were not protestors."

Missouri Gov. Jay Nixon also criticized the violence in a statement Monday, saying that the "entire community was put at risk" by heavy gunfire, after a "day of peaceful marches, prayers and healing."

Read Nixon's full statement below:

"Last night, after a day of peaceful marches, prayers and healing, a number of violent incidents occurred: law enforcement officers were fired upon, businesses were burglarized, a reporter was attacked, a drive-by shooting took place, and the entire community was put at risk by heavy gunfire exchanged among groups of armed criminals. This is a sad turn of events, and I thank the brave and dedicated law enforcement officers who worked into the early morning hours to protect citizens, businesses as well as peaceful protesters and members of the media. Those who terrorize communities with gunfire and commit violence against police officers are criminals, and their reprehensible acts must not be allowed to silence the voices of peace and progress. Over the last year, people of good will across the community have worked tirelessly to bridge divisions, restore trust and build a brighter, safer, and more united future for the region. For the sake of all, it is my hope and expectation that today's events will be peaceful so that these efforts can continue to move the region in a positive direction."