People march in front of Sproul Hall to protest the appearance of Breitbart News editor Milo Yiannopoulos on Feb. 1, 2017, in Berkeley, Calif.
A crowd protesting a far-right commentator's appearance at the University of California at Berkeley hurled smoke bombs, broke windows and sparked a massive bonfire, prompting officials to call off the event.
The decision came two hours before Wednesday's talk by Milo Yiannopoulos, a polarizing editor of Breitbart News, after some 1,500 people had gathered outside the venue.
People protest Yiannopoulos' appearance in Berkeley. Prior to the burst of violence, hundreds of peaceful demonstrators had been protesting the appearance for hours.
Yiannopoulos, a 32-year-old right-wing provocateur, is a vocal supporter of Trump and a self-proclaimed internet troll whose comments have been criticized as racist, misogynist, anti-Muslim and white supremacist. He was banned from Twitter after leading a harassment campaign against "Ghostbusters" actress Leslie Jones.
His visit to Berkeley was sponsored by the campus Republican club. The university has stressed it did not invite him and does not endorse his ideas but is committed to free speech and rejected calls to cancel the event.
Rioters loot and vandalize a Starbucks store during the protest.
Officials said it was a small group of protesters dressed in black and in hooded sweatshirts that showed up as night fell to break windows, throw smoke bombs and flares, and start the raging blaze outside the building.
"This was a group of agitators who were masked up, throwing rocks, commercial grade fireworks and Molotov cocktails at officers," said UC Berkeley Police Chief Margo Bennet.
Bennet said police determined at that point they couldn't guarantee security, canceled the event and evacuated Yiannopoulos from the building.
Protesters march on Berkeley's Telegraph Avenue.
As the evening wore on, crowds of protesters cleared away from outside the building. By 8 p.m. the crowd had thinned and at least 100 protesters that remained danced to a brass band playing music and marched off campus and into a main avenue.
A man pulls a piece of metal out of a window as a flare burns inside a Wells Fargo Bank in Berkeley.
Protesters march holding signs in Berkeley.
Police officers prepare to deploy after a student protest turned violent at UC Berkeley.
Eddy Brock, a free speech advocate, holds his head after he said he was attacked by demonstrators.
President Donald Trump took to Twitter on Thursday morning to comment, tweeting: "If U.C. Berkeley does not allow free speech and practices violence on innocent people with a different point of view - NO FEDERAL FUNDS?"
A rioter paints an anarchy symbol on a Wells Fargo bank during the protest.
A demonstrator creates a fire after during protests.
A protester smashes a bank window.
A protester is carried into a building by police on the UC Berkeley campus.
A bonfire lit by demonstrators on Sproul Plaza on the UC Berkeley campus.