St. Louis County officials declared a state of emergency in Ferguson on Monday, a day after a pair of shooting incidents and aggressive police tactics marred otherwise peaceful protests on the one-year anniversary of Michael Brown's death.

In downtown St. Louis, a short drive from Ferguson, police also arrested a group of prominent activists — including professor Cornel West, and Black Lives Matter leaders Johnetta "Netta" Elzie and Deray Mckesson — for breaching a police line in front of a federal courthouse as part of a protest dubbed "Moral Monday." Multiple others were also arrested, according to reports on social media.

St. Louis County Executive Steve Stenger issued a statement Monday afternoon saying that command of Ferguson's police force had been turned over to St. Louis County Police Chief Jon Belmar.

"In light of last night's violence and unrest in the City of Ferguson, and the potential for harm to persons and property, I am exercising my authority as county executive to issue a state of emergency, effective immediately," Stenger said.

"Chief Belmar shall exercise all powers and duties necessary to preserve order, prevent crimes, and protect the life and property of our citizens," he said.

Moments before Stenger's announcement, the activists in front of the courthouse began to document their arrests live on Twitter.

If I'm arrested today please know I'm not suicidal. I have plenty to live for. I did not resist, I'm just black. — ShordeeDooWhop (@Nettaaaaaaaa)August 10, 2015

Cornel West just got arrested together with around 40 other activists BlackLivesMatter— Lorena de la Cuesta (@LorenadlaCuesta)August 10, 2015

The arrests and state of emergency come after thousands of activists marched in Ferguson to commemorate Brown's death. The unarmed teen was shot by Ferguson police officer Darren Wilson exactly one year ago Sunday.

The day's events were largely peaceful until late in the evening when police shot and critically wounded a young man near the protest after he alleged fired at police. Photos showed a young black man bloodied and lying on the ground, a scene that was eerily reminiscent of Brown's killing the year prior.

Police say the man, who has not yet been identified, was armed with a stolen gun, and that officers returned fire after the man shot first. He was charged with assault on Monday morning.

The young man's father reportedly accused the police of lying about the incident.

Two people were also wounded in a drive-by shooting on Sunday night near the Canfield-Green apartments in Ferguson. The incident was reportedly unrelated to the protests.

The Justice Department has called for a complete overhaul of the Ferguson Police Department after an investigation found that widespread constitutional violations and racist police tactics were commonplace in the city. In the year since Brown's death, police officers have killed at least 1,083 Americans, according to data compiled by VICE News. So far, only 22 of the officers involved in those incidents have been indicted or charged.