
Traffic came to a halt as a boisterous crowd walked in the roadway, some waving Mexican flags. Protesters smashed a window on at least one police cruiser, punctured the tires of a police sport utility vehicle, and at one point tried to flip a police car.
“Dump the Trump,” said one sign. Another protester scrawled anti-Trump messages onto Costa Mesa police cruisers.
“I’m protesting because I want equal rights for everybody, and I want peaceful protest,” said 19-year-old Daniel Lujan, one of hundreds in a crowd that appeared to be mostly Latinos in their late teens and 20s.
By 10:15 p.m., the bedlam had largely subsided and Lt. Mark Stichter of the Orange County sheriff’s department said no major injuries were reported.
Costa Mesa police confirmed that a total of 17 people — 10 males and 7 females — were arrested on suspicion of unlawful assembly. Details on the ages and names of those arrested were not released.
The violent demonstration was underway after Trump concluded his speech before a crowd of thousands.
“This is the anger people have against Trump,” said Jose Cruz, 21, as he pointed to the protesters running in the middle of the street.

Several echoed the comments, saying they were drawn to the streets to counter Trump’s stated policies on immigration and his inflammatory remarks about Mexicans.
The billionaire developer has drawn fierce criticism by claiming Mexico was sending rapists over the border. Later, he called for “a total and complete shutdown of Muslims” entering the U.S.
The county is a major target for Republicans and remains California’s biggest GOP stronghold, though it is less conservative than it was in the days when it anchored the careers of Richard Nixon and Ronald Reagan.
Since then, Orange County’s population has diversified, with an influx of Asian and Latino residents slowly diminishing the political clout of white voters.
Along Newport Boulevard outside the fairgrounds, officers clad in riot gear and mounted horseback lined up across a roadway and slowly pushed the crowd down the street. Helicopters circled overhead.
Watching the chaos unfold, Colby Nicholson, 30, who described himself as a Trump supporter who traveled to the rally from San Diego, wore a “Make America Great Again” hat.
“These people are stupid, but Americans are not stupid in general,” Nicholson said. “These are all underage Mexican high schoolers who have nothing to do.”
Holding a Mexican flag, Juan Carlos, 16, said his parents came to the U.S. from Mexico and that he was protesting to support others like him.
“Donald Trump is worthless,” Carlos said. “There won’t be no United States without Mexicans.”
Law enforcement agencies had deployed additional forces, including 50 Orange County sheriff’s deputies and a dozen Costa Mesa police officers

Costa Mesa officials also set up an emergency operations center across the street from the fairground and the Pacific Amphitheater, where Trump spoke, city spokesman Tony Dodero said.
“We’re prepared for the worst,” he said earlier Thursday.
But as the hundreds of protesters overwhelmed the streets, it was apparent to some that the sizable police presence was wrestling with a larger crowd than expected.
“It definitely got out of control,” said Megan Iyall, 20, who was visiting from Seattle. “I shouldn’t feel this unsafe.”
Earlier in the evening, the rally at the Orange County fairgrounds drew a throng of faithful supporters who proudly showed their allegiance to the leading Republican presidential candidate.