St. Louis (CNN) -- Activist Cornel West was among more than 49 people arrested at the "Moral Monday" march in Ferguson, Missouri, officials said.
A photo from CNN affiliate KMOV-TV in St. Louis showed police in rain gear arresting West, in a black suit, tie and scarf, and others in what appeared to be a parking lot.
Shawn McGuire, a spokesman for the St. Louis County Police Department, said 49 people were arrested.
Police said West and 42 other people were detained at the Ferguson Police Department protest site for disturbing the peace. The protesters tried to push through a police line, he said.
A half-dozen people were arrested at another site for blocking traffic and refusing to clear the street.
As expected, demonstrators demanding the arrest of the police officer who killed Michael Brown took part in a "series of actions" Monday.
Protesters also showed up at a fundraiser in Webster Groves for County Executive candidate Steve Stenger. The event was attended by Sen. Claire McCaskill and at least six demonstrators were handcuffed by police.
There also appeared to be a handful of arrests at a Ferguson Walmart.
On Sunday night, about 2,000 people attended an interfaith rally, where West, who is a professor at New York's Union Theological Seminary and a noted author, was the featured speaker.
Some protesters demanded a chance to speak before West took the stage at St. Louis University's Chaifetz Arena.
"If you can see a dead black boy lie in the streets for four hours and that doesn't make you angry, you lack humanity," a woman, who didn't give her name, told the crowd.
She was referring to how long Brown's body lay on a street before investigating officers removed it after an August 9 encounter between the 18-year-old and police officer Darren Wilson, who authorities said shot the teenager after he attacked him and tried to take his gun.
But witnesses said the unarmed teen had his hands in the air when he was shot.
The shooting prompted weeks of protests in Ferguson, which sometimes became violent when demonstrators and police clashed.
The latest protests, dubbed a "Ferguson October" and "Weekend of Resistance," are taking place in Ferguson, St. Louis and the surrounding area.
Demonstrators are demanding that Wilson be charged with a crime -- a point that West also made.
"Everybody knows if you shoot somebody down, you should be arrested," he said.
He asked the crowd to channel their rage into a plan of action for change.
New wave of protests
Before this week, protests had died down considerably.
But early Sunday, protesters threw rocks at police and tried to storm a QuikTrip store, according to tweets from St. Louis Metropolitan Police Chief Sam Dotson.
In the Shaw neighborhood of St. Louis, protesters have also rallied against the death of Vonderrit Deondre Myers, 18.
Protests erupted there after a white police officer fatally shot the black teenager Wednesday. Authorities said the teenager was armed and fired at the officer, but Myers' relatives said they don't believe the police account.
Two groups of protesters gathered in Shaw before splitting and reconvening at St. Louis University, according to CNN affiliate KTVI-TV in St. Louis.
One group threw a volleyball and jumped rope while chanting, "This is what a game looks like. We aren't playing games."
The group marched to the QuikTrip, a reminder of the violence that happened in Ferguson, where protesters destroyed such a store in the days after the Brown shooting. Police were at the convenience store, which had been closed as a precaution, the station reported.
The crowd prompted Dotson to tweet that demonstrators were trying to "storm" the gas station, and he warned that "protesters engaging in illegal behavior will be subject to arrest."
After clerks locked the QuikTrip door, fearing the store could be looted and burned like the one in Ferguson, police in riot gear used pepper spray on sitting protesters surrounding the QuikTrip, CNN affiliate KPLR-TV reported.
Police told the protesters to disperse, but they wouldn't, so officers moved in, clacking their night sticks on their leg shields as they approached, the station said. Dotson tweeted that protesters threw rocks at police.
Seventeen people were arrested for unlawful assembly, but no injuries or property damage was reported, KPLR said.
'They attacked people'
Ferguson October, the group that helped organize the protests, took issue with Dotson's tweets, saying they only made matters worse.
"Today protestors in St. Louis showed the best of our democracy and the St. Louis police demonstrated the worst of their out-of-control law enforcement agency. The police brutalized peaceful people protesting their brutality," the statement said. "With batons and chemical agents they attacked people peacefully sitting on the ground and the reporters who were there with them."
At St. Louis University, about 1,000 protesters gathered on campus, using the hashtag #OccupySLU to convince people and businesses to donate supplies or join an all-night sit-in. Early Monday morning, about 80 protesters remained on campus, KMOV reported.
"The goal was to occupy SLU and to kind of wake up the campus. I think there's a sense in the community that SLU is kinda shut off from what happens outside of SLU. But this latest incident was six blocks from SLU, so it does affect us," freshman David Gramling told the station.
Early Monday morning, about 200 protesters marched from the site where Myers was shot, holding signs that read, "Black lives matter."
Police with riot gear showed up on a bridge near the St. Louis University campus. The protesters turned on the other side of the street, stayed on the sidewalk and walked past them.
The demonstrations were peaceful, and the protesters said they were serious about keeping them that way. On Sunday, Ferguson October was training protesters in nonviolent civil disobedience.
"Nonviolence is really important because you're not going to change someone's mind by being violent. And also there is just so much more power in taking a stand and doing it nonviolently," Jasmin Maurer, who is taking part in the peaceful training, told KPLR.
Meanwhile, authorities also took additional steps to prepare for the protests, as police told KMOV that every patrol officer in St. Louis -- city and county -- is working 12-hour shifts and days off have been canceled. City police would not say how many officers were working in the area, but a county police sergeant told the station there were about 200 officers in Ferguson alone.
CNN's Bill Kirkos, Sara Weisfeldt, Steve Almasy and Eliott C. McLaughlin contributed to this report.