University of California, Berkeley is on a campus-wide lockdown after protests broke out against Breitbart editor Milo Yiannopoulos, an "alt-right" leader who was scheduled to speak at the school.
Yiannopoulos's event has been canceled, and university police urged students to shelter in place and stay away from the protest area.
Videos from campus show fires breaking out, and students on the scene say firecrackers were thrown.
Yiannopoulos took to Facebook to post about the incident after he left the California campus.
"I have been evacuated from the UC Berkeley campus after violent left-wing protestors tore down barricades, lit fires, threw rocks and Roman candles at the windows and breached the ground floor of the building," he wrote.
"I'll let you know more when the facts become clear. One thing we do know for sure: the Left is absolutely terrified of free speech and will do literally anything to shut it down."
University officials had braced for protesters throughout the day, setting up metal barricades around the building where Yiannopoulos was set to speak.
UC Berkeley police threatening to use tear gas and batons in 10 minutes if hundreds of protesters don't disperse.— Shane Bauer (@shane_bauer) February 2, 2017