Wearing a denim jacket over a sweatshirt resembling an American flag, Yiannopoulos and his entourage showed up shortly after noon at Sproul Plaza on campus and was jeered by a large group of counter-demonstrators. The crowd included a smaller contingent of
Security was tight and only about 100 people were allowed into the plaza after passing through metal detectors.
Yiannopolous spoke briefly to the crowd, sang the National Anthem and posed for selfies with supporters before he was escorted away. The entire event lasted about 20 minutes.
Surrounded by reporters, body guards and screaming protesters, Yianapoulols later told the Times that he had accomplished his mission.
"The purpose of today was to show up on campus no matter what and to let them know we'll be back as many times as it will take," he said.
He said he was pleased with the way things turned out Sunday, saying the event "was fine. It was great."
During Sunday's demonstration, 11 people were arrested, including several for bringing banned items into the plaza area, according to Berkeley and University Police. One person was carrying a shield, orange paint balls, ball bearings, mace, a knife and a stun gun, police said.
Yiannopoulos announced Saturday that he would hold his own forum at the university after the organizers of a far-right speakers series on the campus canceled their event, which was supposed to kick off Sunday.
"We are unable to hold an official UC Berkeley speaking event," Yiannopoulos said. "So we're going to host an unofficial one."
The Free Speech Week event seemed to be in trouble in recent days as organizers failed to meet Berkeley's deadlines for renting indoor venues on campus, while at the same time some scheduled speakers either canceled plans to attend or said they never agreed to appear.
Yiannopoulos, who struggled to help organize the festival, said he still planned to speak on Sunday at Sproul Plaza, where the university's free-speech movement began. The campus has become the national staging ground for confrontations between the right and left
By 11 a.m. Sunday, dozens of counter-protesters from the group Refuse Fascism and others began gathering near the plaza, chanting "No Trump, No KKK, No Facist USA." They faced off with Trump supporters, some wearing red hats emblazoned with the slogan "Make America Great Again," as police in riot gear stood nearby.
The two groups were surrounded by hordes of reporters as several rival demonstrators engaged in heated debate over Yiannopoulos' anticipated appearance.
Campus police set up barricades around the plaza, where backpacks, frozen fruits and other items that could possibly used as a weapon were banned.
Christopher Corsi, 24, said he drove overnight from Phoenix to Berkeley for the chance to see Yiannopoulos. He said he loves how "absolutely outrageous" Yiannopoulos is and how he riles up the left. He said he hopes Yiannopoulos gets the chance to speak.
"I don't think shutting down other people's point of view is good for the left or the right," Corsi said. "I'm not even convinced [Yiannopoulos] even believes what he says. He might just be trolling everybody."
Andrea Grenburg, 34, a Berkeley resident, said she supports free speech, not the kind of hate speech that she believes Yianopoulos promotes, and that is why she wanted to show up to make her views known.
"If no one speaks up, the hatred festers," she said. "When you don't do anything, you can't complain."
Kris Hanson, who has four children, said he drove from out of town to rally with fellow Trump supporters..
"I wanted to stand against the leftist fascists in our community," said Hanson, who was wearing a "Kid Rock for Senate" T-shirt.
Supporters of President Trump and members of the left wing activist groups By Any Means Necessary and Refuse Fascism yelled at each other in roving skirmishes all morning.
Christian Silva, a 29 year old from Fullerton, said he drove up to hear Milo speak and was disappointed the event had devolved into shouting matches.
"They are not here for dialogue," he said of the counter-protesters. "I'll dialogue with anybody about anything but that's not what they want."
Yiannopoulos had complained to reporters that the university tried to sabotage plans for Free Speech Week by making it difficult for organizers to make logistical arrangements and to meet certain deadlines.
But UC Berkeley spokesman Dan Mogulof said such claims were "without basis in fact."
"The university was prepared to do whatever was necessary to support the 1st Amendment rights of the student organization," Mogulof said in a statement.
UC Berkeley has incurred at least $1.4 million in security costs since February, when Yiannopoulos' last appearance there sparked violent protests. The campus spent $200,000 on security for that event, $600,000 for an appearance by conservative firebrand Ann Coulter, whose event ultimately was canceled, and an estimated $600,000 for a talk earlier this month by conservative writer Ben Shapiro, according to the university.
8:45 p.m.: This article was updated with new arrests.
6:30 p.m.: This article was updated with new information from police.
1:00 p.m.: This article was updated with new comments from Yiannopoulos.
12:45 p.m.: This article was updated with new information from the scene.
12:30 p.m.: This article was updated with new comments from demonstrators.
12:15 p.m.: This article was updated with new comments from demonstrators.
11:50 a.m.: This article was updated with new information from UC Berkeley police.
11:10 a.m.: This article was updated with new comments from one of Yiannopoulos' supporters.
10:45 a.m.: This article was updated with new information about UC Berkeley police.