Police in Orange County said "punches were thrown" on Sunday at a political event in Irvine.
The fight took place Sunday at Congresswoman Katie Porter's district town hall meeting, according to police.
Julian Willis, a 51-year-old La Jolla resident, was arrested and given a citation, then released, officials said.
Porter, who represents the 45th Congressional District, had billed the event as Policy in the Park, which kicked off at 3 p.m at Mike Ward Community Park on Lake Road in Irvine.
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Irvine police, who had officers present at the event, said there "were opposing opinions at the town hall. It got heated and punches were thrown. One man received a bloody nose."
The Los Angeles Times reported on Sunday that Porter's "backers [were] scuffling with supporters of former President Trump, who were loudly interrupting the congresswoman as she spoke."
Police identified Willis as a suspect and briefly took him into custody.
Porter is a two-term Democrat who flipped her seat in 2018, unseating incumbent Mimi Walters. During that election year, The Associated Press reported that she "said she was running 'to hold Donald Trump and the powerful special interests in Washington accountable.' ”