Twenty-one officers from various Minnesota law enforcement agencies were injured and more than 102 protestors were arrested as a demonstration on the I-94 freeway in St. Paul turned violent Saturday night, with protestors hurling rocks, bottles, fireworks and bricks at law enforcement officers on the scene.

Hundreds of demonstrators began protesting at the Governor’s Residence in St. Paul Saturday night over the police-involved shooting death of Philando Castile earlier in the week before heading onto the I-94 freeway around 8 p.m., local Fox affiliate KMSP reported.

The interstate was shut down in both directions for more than five hours and the protests eventually turned violent, with demonstrators hurling bricks, fireworks and at least one Molotov cocktail at officers, according to the St. Paul Police Department.

Molotov cocktail thrown at officers. Unclear if anyone injured. #I94closed — Saint Paul Police Department (@sppdmn) July 10, 2016

Another officer hit in the head with a large piece of concrete, possibly dropped from bridge. #I94closed — Saint Paul Police Department (@sppdmn) July 10, 2016

Bricks now being thrown at officers, along with more rocks and bottles. #I94closed — Saint Paul Police Department (@sppdmn) July 10, 2016

Police gave at least 16 orders for the crowd to disperse, eventually using smoke to clear the highway after 1 a.m. Fifty people were reportedly arrested and booked on third-degree rioting charges during the I-94 protest, while another 52 individuals were arrested for public nuisance and unlawful assembly during a separate altercation with police officers around 4 a.m. on Grand Avenue.

In all, 21 officers from several Minnesota law enforcement agencies were injured during Saturday night’s protests.

Arrests on Grand Ave at Dale St during #PhilandoCastile protest in St. Paul. pic.twitter.com/YeTG3s9aC0 — Mara Gottfried (@MaraGottfried) July 10, 2016

Police spokesman Steve Linders told the Minneapolis Star-Tribune that protestors hurled rocks, bricks, glass bottles and fireworks as officers attempted to clear the highway. At one point, protestors reportedly attacked officers with rebar from a nearby construction site.

At a news conference after the incident, St. Paul Police Chief Todd Axtell held up a piece of concrete that was used to attack an officer.

“This is the first time in my 28 years we have observed this level of violence toward our public servants,” Axtell said, according to the Star-Tribune. “It’s really a disgrace.”

More than 100 protestors were also arrested in Baton Rouge, Louisiana Saturday night after blocking a highway to protest the police-involved shooting death of Alton Sterling earlier in the week. Prominent Black Lives Matter organizer DeRay McKesson was among those arrested in Baton Rouge, as was Breitbart News reporter Lee Stranahan.

Follow Daniel Nussbaum on Twitter: @dznussbaum