Hundreds of demonstrators filled the street outside the Orange County amphitheater where Donald Trump held a rally Thursday night, stomping on cars, hurling rocks at motorists and forcefully declaring their opposition to the Republican presidential candidate.
Traffic came to a halt as a boisterous crowd walked in the roadway, some waving American and 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.
One Costa Mesa police officer was struck in the head by a rock thrown by a protestor, authorities said. The officer wasn't injured because he was protected from by his riot helmet.
About five police cars were damaged in total, police said, adding that some will require thousands of dollars' worth of repairs.
"Dump the Trump," one sign read. Another protester scrawled anti-Trump messages on Costa Mesa police cars.
"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.
"I knew this was going to happen," Lujan added. "It was going to be a riot. He deserves what he gets."
Video footage showed some anti-Trump demonstrators hurling debris at a passing pickup truck. One group of protesters carried benches and blocked the entrance to the 55 Freeway along Newport Boulevard, with some tossing rocks at motorists near the on-ramp.
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 17 people -- 10 males and seven 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.
"It's not because he's white -- it's because of what he's said."
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.
Rep. Linda Sanchez (D-Whittier), chairwoman of the Congressional Hispanic Caucus, said there is "no doubt" Trump's candidacy has made the Latino community "a target for hateful rhetoric, and in some cases physical violence."
But destroying public property, she said, is not the answer.
"When we resort to violence, we're playing into the very hands of people like Donald Trump," Sanchez said in a statement released Friday. "I believe the solution must be peaceful protest and more importantly, directing our energy towards shifting our voter registration efforts into high gear."
The county is a major target for Republicans and remains California's biggest GOP stronghold, though it is less conservative than 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 where Trump spoke, a line of officers clad in riot gear and mounted on horseback slowly pushed the crowd down the street as 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."
Costa Mesa resident Cornell Iliescu got into an argument with another anti-Trump protester who was displaying a Mexican flag outside the Pacific Amphitheater box office. Crowds with cameras and smartphones surrounded the two as they debated.
Iliescu told the Daily Pilot that he asked the man why he was proudly displaying a Mexican flag while being in the United States.
"If you come over here, you are welcome, but from now on, you are part of this country," Iliescu recalled telling him.
Law enforcement agencies had deployed additional forces, including 50 Orange County sheriff's deputies and a dozen Costa Mesa police officers to prepare for the night's crowds.
Costa Mesa officials also set up an emergency operations center across the street from the fairgrounds, 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."
David Villanueva attributed the disorder to the last-minute news about Trump's arrival, which he said didn't give civil rights leaders much time to organize the community.
When community organizers have time to plan, he said, protesters are more likely to protest peacefully.
"Rallies that take to the streets are usually led by a group, and are not wild and all over the place like tonight," said Villanueva, a member of Chicanos Unidos in Santa Ana, an organization that was part of the anti-Trump demonstrations.
Thursday's rally also drew a throng of faithful supporters who proudly showed their allegiance to the GOP front-runner.
One man waved a "Gays for Trump" sign while other supporters swapped high-fives as they carried homemade signs reading, "Latinos for Trump." Another sign said, "Black Christian Women for Trump."
In the crowd was Brent Fisher, 65, a retired carpenter, who drove from Apple Valley to attend the rally and hear the Republican presidential candidate speak.
"I love Trump," Fisher said. "He'll stand up and fight and do the things he's talking about."
William Pages, 19, agreed, praising the candidate as an energetic outsider who "says what needs to be said."
Some Trump supporters who had reserved tickets were turned away.
"I'm very disappointed," said Jan Strahl, 66 a Tustin resident who had reserved a ticket but could not get inside the amphitheater to hear Trump.
Those left outside stood facing the horde of anti-Trump protesters, each side taunting the other while police helicopters circled above. As the sun set, the crowd grew more hostile and eventually turned violent.
To Arianna Perez, 19, the flaring of tempers over Trump were a necessary reaction to the inflammatory rhetoric of his campaign.
"We could be peaceful and do things different," she said, "but if we did, we wouldn't get our voice heard."
For breaking news in California, follow @MattHjourno.
Times staff writers Sarah Parvini and Cindy Carcamo and Times Community News writer Bradley Zint contributed to this report.