SAN FRANCISCO (KGO) -- The San Francisco Police Department says they've made an arrest after a free speech rally and protest against Twitter turned violent on Saturday.
Around 12:20 p.m. on Saturday, Philip Anderson, the main event organizer, told officers he was participating in a free speech rally at UN Plaza when he was punched in the face by an unknown suspect. The assault caused him to lose two teeth.
I-TEAM: Proud Boys pledge to return to San Francisco after weekend's free speech rally interrupted
On Monday, SFPD officers arrested a 35-year-old suspect from Watsonville, identified as Adroa Anderson. Officials say the suspect was taken into custody in Oakland and booked on charges of mayhem and hate crime enhancement.
SFPD says although an arrest has been made, the incident continues to be an ongoing investigation. Anyone with information is asked to call the SFPD 24-hour tip line at 1-415-575-4444 or text a tip to TIP411 and begin your text message with SFPD. You may remain anonymous.
I-Team reporter Dan Noyes will have a full report at 6 p.m. on ABC7 News.
Update: SFPD on Tuesday released a correction to the spelling of the suspect's name, Adroa Anderson, previously spelled as Adora.
Original story below:
An event billed as a free speech rally and a protest against Twitter turned violent Saturday. The event featured some well-known conservative personalities, but organizers were forced to cancel the rally minutes after it started.
A large crowd of demonstrators gathered at UN Plaza in San Francisco to oppose a small group, holding what was billed as a free speech rally protesting what they say is Twitter's censorship of some of its content.
"They have no business being here, they're trying to build a fascist movement in this country," said San Francisco resident Carol Seligman.
WATCH: ABC7 I-Team reporter Dan Noyes went to San Francisco to cover the "Free Speech" rally at United Nations Plaza. A lot happened shortly after it started.
The rally was granted a permit from the city.
Some of the speakers expected included well-known President Trump supporters and conservative right personalities, but most never got the chance to be heard.
Tensions quickly escalated, counter demonstrators taunted police, SKY7 was overhead as some kicked barricades.
Police wearing riot gear tried to protect the speakers from the crowd. But many threw bottles at the stage and shouted down the speakers.
Before the event, the main organizer, Philip Anderson said he was attacked and punched getting his front teeth knocked out.
Anderson posted photos to social media of his bloody mouth with a front tooth missing and another hanging loosely. He said anti-fascist protesters attacked him "for no reason."
"Take a good look, you knocked a black man's teeth out," said Anderson.
Minutes later, Anderson announced the rally was over.
RELATED: Group of demonstrators in Redwood City hold rally in support of police, counter protesters blocked by officers
"Too bad it got canceled, that's what happens when you lose free speech, this is what our country has turned into," Anderson told the crowd.
Some counter-demonstrators felt victorious.
"It's tough, I believe in free speech but I'm also anti-fascism," said Elana Thurson-Milgrom from San Francisco.
ABC7's Dan Noyes was also on the ground at the rally and observed an activist with Team Save America being taken away in an ambulance and an injured San Francisco police officer on the ground by San Francisco's United Nations Plaza.
RELATED: 'If there's no justice, how can we have peace?' 'Go-slow' caravan ties up Bay Area bridge traffic
Noyes witnessed attendees of the rally heading down Market Street, even after the rally was canceled.
Rally organizers were escorted away by police. It's still unclear if police made any arrests.