Violence broke out at a pro-Donald Trump rally in southern California on Saturday when a masked man pepper-sprayed the female organiser before demonstrators tackled him to the ground.
Video posted on Facebook from the fracas at Bolsa Chica State Beach, near Los Angeles, shows a man punching the assailant before being pulled away as the masked man runs off.
“It was a quick reaction, there was about 12 of them,” organiser Jennifer Sterling told the Los Angeles Times of her defenders.
Some 2,000 people gathered for the beachfront march were confronted by around 30 counter-protesters, according to local law enforcement.
Thirty-five police and 11 California Highway Patrol officers were standing by and moved in to quell the violence, State Parks Police captain Kevin Pearsall said.
Two people suffered minor abrasions and four people were arrested, he said — three on suspicion of the felony offence of illegal pepper spray use and a woman for misdemeanour assault and battery.
“It was unfortunate there were some incidents,” Pearsall said, adding that the situation could have been worse “considering a number of people and social media coverage.”
Organisers were not immediately available for comment following the rally, intended as a show of support for Trump, first responders and veterans.
The march was one of the dozens planned nationwide, prompting the president to tweeted his thanks “for all of the Trump Rallies today.”
“Amazing support,” he added. “We will all MAKE AMERICA GREAT AGAIN!”