Thousands of people joined the Pride Parade and celebration in San Francisco, but the day ended with some fights, police said.

Sunday’s day of Pride celebrations in San Francisco — a raucous but peaceful parade followed by a Civic Center event with a half-dozen performance stages — ended on a sour note as fights broke out in at least one area and an apparent noxious chemical was fired into the large crowd near the main stage.

Troubles began around 5:25 p.m. when San Francisco police were told of loud disputes near portable toilets that had been set up for event goers, according to Officer Kathryn Winters, a department spokesperson. They arrived to find “a large number of individuals engaged in a physical fight,” Winters said in an email, and broke up the disturbance.

But a few minutes later, at the Kaiser Permanente Main Stage outside City Hall, “an unknown female dispersed a caustic chemical, possibly ‘bear spray’ into the crowd,” Winters wrote.

This incident caused SF Pride to close down all the event stages about 20 minutes before the planned 6 p.m. conclusion of festivities. Pride issued a statement afterward on social media describing the incident as “a person spraying mace into the crowd. Although no one was harmed, we know it was not a pleasant experience. We decided to cut the performance short in the interest of safety.”

As people cleared out earlier than expected, Winters said “a whole bunch of fights between 5:30 and 6 p.m.” were reported to the police. However, none apparently bore any resemblance to the scale of the earlier disruption.

Also around 5:30, when the large fight broke out near Polk and Hayes streets, there were reports of a shooting near Seventh and Market streets, outside the Pride event near UN Plaza. Bars briefly locked their doors to keep people from running out onto sidewalks, and police were called to the scene.

Winters issued a statement an hour or so later that “Officers weren’t able to locate any victims/witnesses,” and that there “doesn’t appear to be merit” to the reports of a shooting.

Officers broke up the fight near Polk and Hayes, the crowd dispersed and no injuries were reported, according to police.

John King is a San Francisco Chronicle staff writer. Email: jking@sfchronicle.com

John King is The San Francisco Chronicle's urban design critic, taking stock of everything from Salesforce Tower to sea level rise and how the pandemic is redefining public space. A two-time Pulitzer Prize finalist and author of two books on San Francisco architecture, King joined The Chronicle in 1992 and covered City Hall before creating his current post. He is an honorary member of the American Society of Landscape Architects.