BERKELEY (CBS/BCN/AP) — University of California, Berkeley police say there have been four to five arrests related to protests in Berkeley, all on city property.

Hundreds protested outside a speech by former Breitbart editor Ben Shapiro but the demonstrations were mostly peaceful.

University spokesman Dan Mogulof called Thursday’s Shapiro speech “a successful event” and says the university is committed to hosting speakers like Shapiro in the future.

• UPDATE: 9 Arrests During Protests Over Ben Shapiro Appearance At UC Berkeley

Hundreds of protesters remained on city streets well into the evening after the event wrapped up.

At least three were arrested for carrying a banned weapon.

Berkeley police say 29-year-old Michael Paul Sullivan of Hayward was arrested, along with 44-year-old Sarah Roark and 20-year-old Hannah Benjamin. Benjamin was also accused of battery on a police officer.

Inside the hall, Shapiro addressed a friendly crowd. He encouraged people to hold civil discussions with people who have different opinions, saying that’s what America is all about.

He condemned white supremacists as “a very small select group of absolutely terrible people who believe absolutely terrible things.”

The campus and surrounding Berkeley streets were under tight security after a series of previous events turned violent.

Onlookers told KPIX 5 that a female activist had been stopped from bringing a sign into the designated protest area where Telegraph Avenue runs into the edge of campus because it did not meet campus guidelines for signs at the event. She was escorted away from the protest area.

Onlookers also said that the woman who was arrested spat on officers. That is considered assault and she was quickly put into zip ties and taken away by officers.

Authorities took unprecedented measures on Thursday to keep the protests against Shapiro speaking at Zellerbach Auditorium peaceful.

Work crews erected concrete barriers on the streets leading into campus. Busy Bancroft Way was walled off and all parking on it banned. A heavy police presence was already visible on the streets by 12 p.m.

Those attending the speech at 7 p.m. waited in long lines to pass through a metal detector prior to entering Zellerbach. Police in riot gear seemed to be everywhere.

More police move into position to surround the part of campus where @BenShapiro will speak. #benspeaks pic.twitter.com/C4JXMtTs0y — Joe Vazquez (@joenewsman) September 15, 2017

Authorities said that they planned to confront any protesters wearing masks to keep them off of campus and would have “zero tolerance for violence” in the designated protest area.

Authorities sealed off the campus’ central hub, Sproul Plaza, the student union and Zellerbach Hall, creating a perimeter around several buildings. There were checkpoints on campus where only ticket holders and students who had classes on the other side of the barrier were allowed through.

The walkway in front of Zellerbach Hall — the site of Thursday’s speech — was littered with chalk messages Thursday afternoon condemning fascism and xenophobia.

Nearby, the Bank of America boarded up its ATMs to prevent vandalism during the protest.

Earlier in the day, UC Berkeley freshman Matthew Barnett said he — like many of his fellow students — was a little stunned as he looked over the preparations underway on campus for the speech by Shapiro.

“The idea that we should have all this security just to have one person speak is a little insane,” Barnett told KPIX 5.

Long line to see #BenAtBerkeley now going through metal detector pic.twitter.com/4Rs8s6Flu8 — Joe Vazquez (@joenewsman) September 15, 2017

Meanwhile, law student Anthony Jenny said he was going to the speech to hear what Shapiro had to say.

“They (the protesters) are demoting Ben Shapiro for being a fascist. Meanwhile they are targeting people with conservative views and trying to ruin their lives,” he told KPIX 5.

“We do not initiate violence,” said Sunsara Taylor, a member of Refusefascism.org. “But we do believe people have the right to self-defense. It’s a legal and a moral right.”

University officials said they would not allow anyone wearing masks, carrying shields or anything that can be used as a weapon near Zellerbach Hall.

“There will be “an increased and highly visible police presence,” the university said in a statement.

And for the first time in two decades, officers were authorized to use pepper spray to control violence after the City Council modified a 1997 ban at an emergency meeting this week.

City of Berkeley Police Chief Andrew Greenwood said officers would make “very strong, rapid arrests” of protesters wielding weapons and wearing masks.

The city and the UC Berkeley campus have become a flashpoint for the country’s political divisions, drawing extremist groups from the left and right.

Four political demonstrations have turned violent in Berkeley since February, prompting officers to come up with new strategies to control rowdy and sometimes dangerous crowds.

“We have seen extremists on the left and right in our city,” said Berkeley Mayor Jesse Arreguin, a Democrat who backed the police request to use pepper spray. “We need to make sure violence is not allowed.”

Shapiro was invited to speak by campus Republicans, who say the liberal university stifles the voice of conservative speakers.

The Berkeley College Republicans invited right-wing provocateur Milo Yiannopoulos to speak last February, but the event was abruptly canceled when masked left-wing anarchists rioted outside the event to shut it down.

Police and UC Berkeley officials were criticized at the time for giving demonstrators wide latitude and standing aside as the anarchists hurled Molotov cocktails at officers and caused $100,000 worth of damage.

Tighter security measures were expected to disrupt campus life Thursday and later this month, when Yiannopoulos says he plans to hold a “Free Speech Week” on campus with a lineup of controversial figures including conservative commentator Ann Coulter and Steve Bannon, Trump’s ex-chief strategist who returned to Breitbart News.

Thursday’s speech is being watched as a warm-up act for later this month, although campus officials say that event is not yet confirmed.

Sociology professor Michael Burawoy, who is chairman of the Berkeley Faculty Association, says frustration is growing over the disruptions.

“There are faculty who don’t think the campus should be the site of this, what they call, political circus,” Burawoy said, adding that the headline-grabbing visits by controversial speakers put the university in a no-win situation.

“We bring them on campus and allow them to speak and we encourage both right- and left-wing groups” to hold potentially violent protests, he said. “If we exclude them, they say Berkeley doesn’t believe in free speech. It’s a lose-lose situation.”

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