[Photo: Milo Yiannopoulos, Senior Editor, Breitbart News]

President Donald Trump issued a tweet threatening the University of California at Berkeley with a cut in federal funding after the school canceled a Breitbart editor's speech amid violent protests.

“If U.C. Berkeley does not allow free speech and practices violence on innocent people with a

different point of view - NO FEDERAL FUNDS?”

The school went into lockdown on Wednesday amid a violent protest over a planned appearance by right-wing provocateur Milo Yiannopoulos. Yiannopoulos' scheduled appearance came on the day that his college grant program for white males began taking applications. Critics blasted it as fanning white nationalism. In July, he was banned from Twitter for tweeting abusive comments toward specific users, including African-American comedian Leslie Jones.

Demonstrations broke out and a small group of protesters wearing black and hooded sweatshirts broke windows threw smoke bombs and flares. "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 Bennett.

Bennett said police determined at that point they couldn't guarantee security, canceled the event and evacuated the Breitbart News editor from the building. School officials said on Twitter that the campus was on lockdown.

There were no immediate reports of arrests or serious injuries.