Story highlights Police arrest 35 people protesting near Interstate 70

Bricks, stones, rocks and bottles are thrown, police say

Protesters moved to downtown Ferguson

Protest comes after contentious City Council meeting, Ferguson's first since shooting

Police on Wednesday arrested dozens of protesters threatening to shut down a portion of Interstate 70 near Ferguson, Missouri.

Some demonstrators threw rocks at police during the emotionally charged protest, aimed at persuading Gov. Jay Nixon to appoint a special prosecutor to investigate last month's shooting death of 18-year-old Michael Brown . CNN witnessed about two dozen people being taken into custody after refusing to leave the street.

A crowd of protesters started gathering Wednesday afternoon on entrance and exit ramps to the interstate, stopping traffic on a nearby road but not the interstate itself.

As of 7 p.m., state troopers had arrested 35 people. Most of them face unlawful assembly charges, Missouri Highway Patrol Sgt. Al Nothum said. Four are charged with assault on a law enforcement officer.

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Police say bricks, stones, rocks, glass bottles and water bottles were thrown at officers. One protest organizer told CNN the objects were thrown by "professional agitators," not protesters.

Local authorities ordered protesters not to disrupt interstate traffic and stopped protesters from blocking the highway.

before the protest, "Attempting to block an interstate highway is unsafe and unacceptable. ... People trying to shut down I-70 would not only create a very serious hazard for themselves, but also for motorists simply trying to get home from school or work," Missouri Highway Patrol Capt. Ron Johnson saidbefore the protest, according to CNN affiliate KMOV

Demonstrators who weren't detained headed to downtown Ferguson to protest outside the police headquarters there.

A grand jury is hearing the Brown case and will determine whether Ferguson Police Officer Darren Wilson will face any charges.

The protest comes amid a busy week in the Brown case.

On Tuesday night, the Ferguson City Council met for the first time since the shooting, and on the agenda was the creation of a citizen review board to work with the Police Department.

The meeting quickly turned rowdy, though, with some in attendance chanting Brown's name and shouting at council members, according to various media reports.

"You have the Michael Brown movement in your face because of your ongoing neglect," one woman told the council.

Added another, "We're not going to let you go back to business as usual."

The ordinance to create the citizen review board was read Tuesday, but it requires a second reading before the council can vote on it, Mayor James Knowles told the crowd, according to CNN affiliate KPLR

Also Tuesday, Circuit Court Judge Ellen Levy Siwak denied a request from the St. Louis Post-Dispatch that Brown's juvenile records be released, the paper reported . The paper sought the release of the records because there is heavy public interest in Brown's history.

Though the records weren't released, a juvenile court lawyer said Brown had no serious felony convictions as a juvenile, and he was facing no charges at the time of his death.

Earlier Tuesday, Brown's family members appeared alongside members of the NAACP and the Rev. Al Sharpton's National Action Network, demanding that Wilson be arrested for Brown's death.

"Darren Wilson should be arrested, booked, fingerprinted and photographed," Brown family attorney Anthony Gray said during the Tuesday news conference.