The university was placed on lockdown as the sold-out appearance by Milo Yiannopoulos was cancelled.
Violent protests erupted on Wednesday at the University of California at Berkeley over the scheduled appearance of a controversial editor of the conservative news website Breitbart.
Fans and foes agree that Milo Yiannopoulos specializes in controversy. The polarizing editor from Breitbart News is a self-proclaimed internet troll who has been criticized as racist, misogynist and white supremacist.
His scheduled visit Wednesday to the University of California at Berkeley has raised an issue facing campuses across America at the dawn of the Trump presidency: What is the line between free speech and hate speech?
Hundreds of students and other protesters chanting "shut him down" smashed windows at the campus, set wooden pallets on fire and threw fireworks and rocks as police in full riot gear responded with tear gas.
The university was placed on lockdown as the sold-out appearance by Milo Yiannopoulos, a conservative firebrand, was cancelled in early evening.
Yiannopoulos, who is technology editor for the news website, is known for his provocative social media posts and was banned from Twitter in July for fuelling abuse directed at "Ghostbusters" actress Leslie Jones.
The events at Davis and Berkeley were organized by conservative student groups.
The British journalist is a vocal supporter of Donald Trump - nicknaming the US president "Daddy" during his election campaign - and has become one of the faces of America's "alt-right" movement.
Yiannopoulos rejects accusations he is racist or white supremacist, saying his boyfriend is black and his humor is taken too literally in today's politically correct culture.
Similar rowdy protests at UC Davis on January 13 prompted campus Republicans to cancel his appearance at the last minute.
The events at Davis and Berkeley were organized by conservative student groups. A similar invitation to speak at UCLA was rescinded and Berkeley was to be the last stop of his tour.
Officials at the three University of California campuses stressed that they did not invite Yiannopoulos or endorse his ideas but were committed to free speech.
The Berkeley Republican Club says it has no plans to cancel the event because that would send a message that intimidation and violence can win.
More than 100 UC Berkeley faculty members had signed two letters sent last month to the school's chancellor, urging him to cancel the event.
"Although we object strenuously to Yiannopoulos's views - he advocates white supremacy, transphobia and misogyny - it is rather his harmful conduct to which we call attention in asking for the cancellation of this event," read one of the letters.
They cited as one example an incident in December at the University of Milwaukee where Yiannopoulos -- a gay crusader against "political correctness" -- openly mocked a transgender student, displaying her name and photo on screen.
(With inputs from AFP and AP)