BERKELEY (CBS SF) — As crews continued a massive cleanup operation at UC Berkeley the day after the destructive protest against Breitbart editor Milo Yiannopoulous, on Thursday some were questioning why police did not move to arrest those who caused the most damage.

Police officers came prepared in riot gear and about 100 outside agitators aimed at causing chaos came armed with sticks and rocks. Some set off fireworks in the middle of Sproul Plaza. Others threw objects at UC police.

And as the violence escalated, officers pulled back.

Susan Walsh was stuck on the second floor of UC Berkeley’s student union building where she was waiting to hear Yiannopolous speak when protests outside turned violent.

“It was a riot. It felt like a war zone,” said Walsh. “Absolutely felt like a war zone.”

Police gathered on the balcony demanding that the crowd disperse, but made no moves against the protesters.

“They were equipped to shoot rubber bullets or what have you, and they really didn’t do anything. And, I thought, ‘We are sitting ducks,'” siad Walsh.

When asked why police didn’t move in and stop the rioters, UC Berkeley spokesperson Dan Mogulof replied, “Police tactics are driven on a campus by need, the non-negotiable need to protect our students and ensure their well being.”

University officials said police decided to stay back to prevent injuring innocent protesters and bystanders who could have been hurt if officers waded into the crowd.

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“In the context that we have had no reports of serious injuries, we are satisfied with the police department’s performance,” said Mogulof.

The protest caused more than $100,000 in damage to the UC Berkeley campus, not counting more than a dozen businesses that were

vandalized in the city’s downtown area and Telegraph corridor, university officials said.

Despite the destruction and violence, there was only one arrest by university police. City of Berkeley police, who monitored the demonstration once it left the university, said they made no arrests.

University police said that some members of the crowd were attacked by protesters and then rescued by police. UC police said there were

six reports of minor injuries.

Berkeley police said once the protest moved into city streets, rioters vandalized 15 buildings. Again, police did not move to take the vandals into custody.

“Our primary objective with the resources we had was the protection of life, said a Berkeley police spokesperson.

Rudra Reddy is with the Berkeley College Republicans, the group that invited Yiannopoulos to campus, sparking the outrage.

“They tried their best, but what can you do when you have people throwing fire crackers at policemen? It’s just ridiculous,” said Reddy

The university allowed the event in the name of free speech. University officials said about 1,500 protesters remained peaceful.

President Trump tweeted about the protest early Thursday morning, threatening to withhold funds from the school.

If U.C. Berkeley does not allow free speech and practices violence on innocent people with a different point of view – NO FEDERAL FUNDS? — Donald J. Trump (@realDonaldTrump) February 2, 2017

“It’s a bargaining chip he’s using right now,” said Reddy. “I think the president has used Twitter very effectively and i think he should continue to do so.”

In a statement Thursday morning, Berkeley Mayor Jesse Arreguin said, “Unfortunately, last night, a small minority of the protesters who had assembled in opposition to a speaking engagement featuring a prominent white nationalist engaged in violence and property damage.”

“They also provided the ultra-nationalist far right exactly the images they want to use to try to discredit the vast majority of peaceful protesters in Berkeley and across America who are deeply concerned about where our country is headed,” Arreguin said.

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