CNN  — 

At least 41 people were arrested Wednesday in a rush hour protest that briefly shut down Interstate 35 in Minneapolis, Minnesota State Police said.

More than 40 people of various races spilled onto I-35W Wednesday morning to protest the death of Philando Castile, who was fatally shot by a police officer during a July 6 traffic stop in Falcon Heights, Minnesota.

Using cars to block the freeway protesters took over all southbound lanes, backing up traffic for five miles for more than an hour. They took up various positions on the roadway, some holding hands in a human chain, others sitting on the ground, as they chanted “Black Lives Matter.”

The protesters called themselves "non-black allies."

It was one of several gatherings across the country Wednesday in a sustained chorus of discontent since the shooting deaths last week of Castile and Alton Sterling in Baton Rouge, Louisiana.

Hundreds of people gathered outside the Boston Police Department Wednesday night and marched behind a banner reading “Unite to Fight.”

In Baton Rouge, people continued to keep vigil outside the Triple S convenience store where Sterling died. Local pastors David and Frankie Smith set up a makeshift voter registration drive outside the store.

By 5 p.m., six people had registered, they said.

“We need elected officials who are going to work with all of the people, not just some of the people.” said 54-year-old Frankie Smith.

Protests, arrests, lawsuits

Last week’s peaceful vigils and memorials evolved into demonstrations where tense encounters between police and protesters have led to hundreds of arrests in recent days. A deadly sniper attack on Dallas police officers at one of those demonstrations broadened the divide between pro-law enforcement camps and those seeking charges for the officers involved in the shootings.

In response to clashes between police and demonstrators in Baton Rouge this past weekend, local organizing groups and the American Civil Liberties Union of Louisiana filed a lawsuit against the Baton Rouge Police Department on Wednesday.

The lawsuit accuses the department of violating protesters’ First Amendment rights, alleging police used excessive force, physical and verbal abuse and wrongful arrests to disperse protesters.

A spokesman for the department declined to comment.

More arrests expected

“Non-black allies” were responsible for the action Wednesday in Minneapolis, said Nekima Levy-Pounds, president of the Minneapolis NAACP, which has organized rallies and protests since Castile’s death.

The Minnesota State Patrol, Hennepin County Sheriff’s deputies and University of Minnesota police responded to the area and closed the freeway “for the safety of the protesters, motorists and first responders,” the Minnesota State Police said.

Troopers arrested 41 people on the freeway after about an hour and impounded four vehicles used to block traffic. The freeway reopened shortly after 9:15 a.m.

Morning commuters were backed up for mile.

Protesters will face charges for their actions, the statement said.

“The State Patrol supports the right to exercise one’s First Amendment rights, but the freeway is not the place to do so,” said Col. Matt Langer, Minnesota State Patrol chief.

“The closure of an interstate freeway for the purposes of a demonstration is unacceptable. They are used by everyone and are an artery for emergency vehicles. It is illegal to walk on the freeway and blocking traffic is dangerous for both pedestrians and motorists.”