Following a busy week of appearances to promote his new book, Donald Trump Jr. faced not the press, but angry students at UCLA on Sunday. Protests broke out hours before the president's son arrived on campus to discuss "Triggered: How the Left Thrives on Hate and Wants to Silence Us."

Atlas Winfrey, an organizer with the activist group Refuse Facism, told CBS Los Angeles Trump Jr. should not have been allowed to speak at UCLA and President Trump should not be in office.

"Ourselves and students and people all across the country must demand that the Trump-Pence regime must step down now," Winfrey said. "We can't wait for 2020. We can't sit around and wait for how many more immigrant children to die."

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Refuse Facism, which holds anti-Trump protests across the U.S., said it was responsible for planning the UCLA demonstration.

Protesters opposed to President Trump hold signs during a protest outside a book promotion by Donald Trump Jr. at the UCLA campus in Westwood, California on November 10, 2019. MARK RALSTON/Getty Images

"When you actually do look at everything the people in the White House are unleashing, the white supremacist terror, locking immigrant children in concentration camps, that's why we're out here, with the demand Trump-Pence out now," protester Michelle Xai told CBS Los Angeles.

But supporters of President Trump were also present ahead of Trump Jr.'s arrival. "He's brave, he takes on the bullies and he's unleashed by it and I love that," supporter Randy Simer told CBS Los Angeles.

During the packed event, Trump Jr. and and his girlfriend, former Fox News cohost Kimberly Guilfoyle, were often interrupted and booed by members of the audience.

According to The Guardian, some of the loudest outcry appeared to come from conservatives upset that Trump Jr. would not take questions. "Q and A! Q and A!" the crowd chanted.

The event ended abruptly due to continuous disruption from protesters, CBS Los Angeles reports.

In a statement to CBS News, Turning Point USA, a conservative nonprofit organization that organized the event, said the decision to cancel the Q&A portion of the talk was made days earlier after TPUSA was "made aware of a pre-planned effort to disrupt the event." The event was not cut short because in lieu of a Q&A, the guests were given more time to speak, according to TPUSA.

Outside the event, police in riot gear kept protestors at bay using barricades. No arrests were made and police said they had no problems.

Supporters of President Trump yell at counter protesters outside a book promotion by Donald Trump Jr. at the UCLA campus in Westwood, California on November 10, 2019. MARK RALSTON/Getty Images

Trump Jr. had posted on Instagram stories ahead of the UCLA event, saying, "I'm sure you'll hear about it," but did not post anything following the protests.

While promoting the book in California, Trump Jr. also held an event at Reagan Library, which he described as an "amazing evening" on Twitter.