Police and demonstrators clashed at a rally for Republican presidential candidate Donald Trump in southern California late Friday, leading to the arrests of 35 people.
Police in San Diego declared the initially peaceful gathering of around 1,000 people illegal when the crowd's behaviour became "unlawful," the department said.
There were no injuries and no property damage was reported, police said on Twitter.
The clashes broke out after Republican presumptive presidential nominee addressed supporters at the San Diego Convention Center.
Protestors gathered outside the venue, and became unruly after Trump left around 4:30 pm (2330 GMT), the LA Times reported.
Police moved to disperse the crowd after bottles were thrown. Calm was restored by 6 pm, the report said.
Trump has won 1,238 delegates, one more than needed to win the Republican nomination, according to an Associated Press tally.
His outspoken comments, including the campaign promise to build a wall on the border with Mexico, just 10 kilometres south of Friday's rally venue, have garnered popular support but also sparked virulent criticism.
At a campaign rally in the south-western state of New Mexico on Tuesday protesters outside the arena in the city of Albuquerque where trump was speaking threw burning T-shirts and bottles at police. The protesters and Trump supporters also yelled insults at each other as the rally ended.