About 7,000 people flooded Downtown Berkeley on Sunday in a confrontation between “alt-right” ralliers and counterprotesters that ended in pepper spray, purple smoke and 13 arrests.

Around 11 a.m., counterprotesters who marched from Ohlone Park in North Berkeley stood face to face with a small group of right-wing and white nationalist marchers at Martin Luther King Jr. Civic Center Park. The protesters had gathered as holdovers from the “No to Marxism in America” protest, which was canceled days before because of safety concerns.

Berkeley counterprotesters dwarfed those rallying for the “alt-right,” a demographic similar to a right-wing free speech rally in Boston on Aug 19. This pattern of disparity prompted police to escort ralliers out of dangerously outnumbered situations in both cities.

Several fights began to break out between the opposing sides, leading to arrests for a variety of violations, according to Berkeley Police Department.

“Tensions between protesters and counter-protesters are escalating,” BPD said in a Nixle alert. “If near Civic Center Park, leave immediately.”

About 1:30 p.m., police abandoned the security line at the Center Street and Milvia Street entrance to Civic Center Park, at which point protesters in the area stormed the park. Antifa members climbed over police barriers with flares, spraying plumes of purple smoke into the air.

Some groups also organized demonstrations at other locations in Berkeley, including the UC Berkeley West Crescent Lawn and Ohlone Park, to protest the “alt-right” rally. Protesters at the Crescent Lawn and Ohlone Park started marching toward Civic Center Park about noon.

Barbara Roose, activist and Holocaust survivor, was one of many who went to Civic Center Park to protest the “alt-right” rally.

“Hate speech leads to Holocaust. I’m a Holocaust survivor, and I lost a sister to the Holocaust, and there is Holocaust here in the United States,” Roose said. “I’m concerned because allowing hate speech … has led to … mass murder in other racist countries.”

The park, mixed with “alt-right” supporters and protesters, was surrounded by barricades that BPD had set up before the rally. About 12:15 p.m., counterprotesters in the park were chanting, “We’re here, we’re there, we fight the KKK!”

Approximately 50 police officers were spread out around the four entrances to the park.

“I’m here because we’ve known that there’s racism … around the country forever, but since Trump was elected, it’s emboldened them, and we want to show that racists and white supremacists need to crawl back under the rocks from where they were,” said Oakland resident Adam Gold, who attended the counterprotest in Ohlone Park. “If they plan to protest and be violent, we are going to stop them — just how we are going to stop the white supremacists in the White House.”

One man at Civic Center Park held up a sign that said “God Bless Donald Trump,” while the counterprotesters around him yelled, “Impeach Trump.” Arthur Schaper, a South Bay blogger who also attended the rally, wore a “Make America Great Again” hat as he spoke to the crowd.

“I think that Black lives matter, but I think my life matters too,” Schaper said to the crowd.

Erin Smith, a transgender Trump supporter, was shouted down by the crowd at the rally. She said that she voted for Trump but is “not political.” She added that she went to talk to some protesters and they became aggressive.

About 1:15 p.m., BPD officers on Allston Way and Milvia Street began putting their gas masks on, and around 3:15 p.m., the crowds began to disperse, according to a Nixle alert sent out by BPD.

Mayor Jesse Arreguín issued a press release at about 5 p.m. applauding the large numbers of people who came out to counterprotest, despite having previously asked community members to stay away. Arreguín praised those who peacefully opposed bigotry, but he criticized a small group of protesters who took to violence — “Fighting hate with hate does not work and only makes each side more entrenched in their ideological camps,” Arreguín wrote.

Oakland resident Serena Perez, who came to Civic Center Park to protest the alt-right, emphasized the importance of speaking out against the rise of white supremacy.

“You cannot let this type of disease fester and grow. If we don’t come out here and stop it, it will grow,” Perez said. “I 100 percent recognize that there’s a possibility for violence … (But) if you’re not willing to stand for something … then you’re not living at all.”

Sakura Cannestra, Gibson Chu, Rachael Cornejo, Chantelle Lee, Audrey McNamara, Francesca Munsayac, Malini Ramaiyer, Harini Shyamsundar, Amber Tang, Henry Tolchard and Ashley Wong all contributed to this report.