Donald Trump Jr., the president's eldest son and putative author, was heckled and forced to flee by a California crowd at the launching of his new book at the University of California Los Angeles (UCLA) after he refused to engage in a question and answer event.

His new book, "Triggered: How the Left Thrives on Hate and Wants to Silence Us," accuses liberals of censorship and stifling press freedoms of conservatives like himself and his father. Observers noted Don Jr.’s refusal to answer questions from the audience was at odds with his book's thesis.

Oddly, the heckling began not with liberals in the audience but with a small right-wing fringe group of America Firsters who believe the Trump administration has been taken over by internationalists, free-traders and apologists for mass immigration, according to The Guardian.

Don Jr. tried to silence the rising chants of “Q&A!”, “Q&A!” by saying “I'm willing to listen ...”

Those in the audience of 450 persons responded with, “Q&A!”, “Q&A!” to which Don Jr. said, “We'll go into the lion's den and talk …”

The audience again replied, “Then open the Q&A!”

UCLA's student newspaper, The Daily Bruin, said the event "contradicted itself" for not allowing questions. One student at the event told the paper Don Jr. was "scared of being triggered by the questions people ask."

After 20 minutes into the event that was billed for two hours, Don Jr. and his girlfriend, Kimberly Guilfoyle, stormed off the stage pursued by loud "Boos!" from the crowd. Don Jr. later said he wanted to avoid the possibility that video and voice recordings of the Q&A, which would have been posted to social media, being used by left-wing to further damage his father's reputation.

UCLA students also protested Don Jr.s invitation to their campus. Hundreds of demonstrators displayed placards protesting Don Jr.'s visit earlier Sunday shouting, "UCLA protects fascists," according to media reports.

Ricardo Vazquez, a UCLA spokesman, defended Don Jr'.s visit. He told Business Insider that allowing someone to speak on campus "is not an endorsement of their views. UCLA is committed to equity, inclusion and mutual respect as well as protecting the physical safety of everyone on campus. This includes their right to speak, be heard, hear others and peacefully dissent."

Turning Point USA (TPUSA), which organized the event, said it made the decision to cancel the Q&A after being notified of pre-planned protests against Trump and Guilfoyle.

"This was a Turning Point USA event and it was our organization's decision to cancel the Q&A portion days before after we were made aware of a pre-planned effort to disrupt the event," said a statement from TPUSA.

TPUSA is a far-right conservative nonprofit organization accused of engaging in racist practices and being part of the Alt-Right racist movement. One of its aims is to "combat liberalism on college and university campuses."

Donald Trump Jr. Donald Trump Jr. said he met a woman in June 2016 — who turned out to be a Kremlin-connected lawyer. In this photo, Trump, Jr. attends the 139th White House Easter Egg Roll on the South Lawn of the White House in Washington, D.C., April 17, 2017. Photo: Getty Images