FERGUSON, Mo. -- After a weekend of protests, unrest and violence in Ferguson, including an officer-involved shooting on Sunday, the St. Louis County Executive has issued a state of emergency in St. Louis County.

Police detained several protesters in St. Louis at a planned rally in front of the courthouse on Monday to mark the death of Michael Brown in Ferguson, Mo., one year ago. Small groups of protestors remained in front of the courthouse Monday afternoon after others were detained.

The St. Louis County Executive Steve Stenger said in a statement that in light of Sunday night's violence and unrest in Ferguson, and the potential for harm to persons and property, a state of emergency was being declared effective immediately.

"The recent acts of violence will not be tolerated in a community that has worked so tirelessly over the last year to rebuild and become stronger," he said in the statement. " The time and investment in Ferguson and Dellwood will not be destroyed by a few that wish to violate the rights of others."

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In the statement, Stenger said St. Louis County Police Chief Jon Belmar shall immediately take over the operation of police emergency management in Ferguson and the surrounding areas.

Meanwhile, prosecutors filed 10 counts against Tyrone Harris on Monday afternoon, the 18-year-old black suspect who was critically wounded after being shot by police Sunday night in Ferguson.

At the height of what was already a rowdy protest in which rocks and bottles were thrown at officers, gunshots rang out from the area near a strip of stores, including some that had been looted. St. Louis County Chief Jon Belmar believes the shots came from about six different shooters. What prompted the shooting wasn't clear, but Belmar said the groups had been feuding.

Protests over the weekend marked the one year anniversary of the death of Michael Brown in Ferguson. Brown's death helped spur a national "Black Lives Matter" movement that raised difficult questions about law enforcement attitudes toward minorities and the militarization of police.

Michael Brown Sr. led a march on Saturday in Ferguson that started at the memorial on Canfield Drive that marks the site where Brown was fatally shot.

Brown's father said a lot of families in the St. Louis area and across the nation are hurting because they've lost loved ones to police violence. Though some groups are pledging civil disobedience in the St. Louis region, Brown urged everyone to mark his son's death in peace.

Happening now outside the Federal Building on what's being called #MoralMonday pic.twitter.com/tWhIPa0ey8 — KMOV (@KMOV) August 10, 2015

"No drama," he said. "No stupidity, so we can just have some kind of peace."

Protests over the weekend were mostly peaceful, but were marred by gunfire Sunday night.

NAACP board member John Gaskin III says some people may not believe the police account of the incident overnight that left a shooting suspect critically wounded, noting "there's still a tremendous level of distrust between law enforcement and the community."

Nonetheless, Gaskin says he expected Monday night to be free of reactive violence, thievery and destruction.

Gaskin also credited St. Louis County's police chief, Jon Belmar, with distinguishing between activists who marched respectfully to commemorate Brown's death and those who went "off track" and turned violent Sunday night.