Dozens of demonstrators gathered at the University of California, Berkeley, Sunday ahead of right-wing provocateur Milo Yiannopoulos' planned speech.
Yiannopoulos' previously attempt to speak at the university in February but that was shut down by masked anarchists who rioted on campus.
On Sunday, police were working to keep demonstrators and supporters of the right-wing provocateur separated at the university's Sproul Plaza.
The conservative student group Berkeley Patriot, which planned a four-day event dubbed "Free Speech Week," canceled due to safety concerns.
"It is extremely unfortunate that this announcement was made at the last minute, even as the University was in the process of spending significant sums of money and preparing for substantial disruption of campus life in order to provide the needed security for these events," UC Berkeley spokesman Dan Mogulof said in a statement.
Yiannopoulos, however, said he and his fellow right-wing commentators, would still hold Sunday's rally.
"We will be expressing our constitutional rights to free speech, free expression, on Sproul Plaza, the home of the Free Speech Movement, tomorrow as planned, with or without student help, with or without the cooperation of UC Berkeley itself," he said Saturday.
The Associated Press contributed to this report.