OAKLAND (CBS SF) — Hundreds of protesters angered over the Wisconsin police shooting of Jacob Blake marched peacefully in the streets of Oakland late Wednesday night before splinter groups unleashed a wave of vandalism that left store windows slammed, vehicles burned and smoke rolling out of the Alameda County courthouse.

The demonstration came in the wake of the Blake shooting, a black man who was shot, point blank, 7 times in the back.

The crowd began gathering in the early evening hours at Frank Ogawa Plaza on Broadway, downtown Oakland’s main street.

Oakland police said it soon grew to several hundred who began marching toward police headquarters that was ringed by barricades and a line of riot geared officers.

Over a bullhorn, police told demonstrators they had the right to peacefully protest, but if they engaged in acts of violence and vandalism they would be arrested.

About 11 p.m. protesters walked down the Grand Avenue off-ramp from Interstate 580 after temporarily stopping traffic on the freeway, and then continued throwing objects at police.

Within hours, groups broke off and went on a wave of vandalism down Broadway, Lakeshore Ave. and Clay St. Windows were smashed at a Whole Foods Store, a building housing offices of Edward Jones and then they targeted the Alameda County Courthouse.

Doors were battered open at the courthouse, an arson fire was set inside. Oakland firefighters quickly extinguished the blaze, but not before it damaged the inside of the building.

“I am angry! I am angry! … I ain’t here to talk about workers,” a man told the crowd. “I’m here to talk about Black people getting killed in the **** street!”

Earlier, police had urged calm.

The City of Oakland released a statement, saying “We celebrate passionate protest, but remind Oaklanders that when they attend protests after dark they may be providing cover for agitators who are more intent on vandalism and stoking civil unrest than advancing social justice.”

Oakland police said there were no initial reports of officers being injured. Several arrests were made.

Crews were seen all around the downtown area early Thursday, repairing smashed windows and installing plywood over the damage.