Outside Republican presidential candidate Donald Trump’s rally in San Jose on Thursday, his supporters were chased down, punches were thrown and “Make America Great Again” hats were set alight. (Jenny Starrs/The Washington Post)

Democrats and Hispanic activists said Friday that they are increasingly alarmed by a spate of violence at Donald Trump rallies instigated by anti-Trump protesters, fearing that the incidents — widely viewed on television and social media — will only help the GOP candidate and undermine their attempts to defeat him.

The latest flash point came Thursday in downtown San Jose, where a demonstration outside a Trump campaign rally quickly escalated out of control. Several protesters assaulted Trump supporters, ripped pro-Trump signs away from them and stomped on vehicles in the area. A flurry of video clips circulating Friday morning showed bystanders who sustained bloody injuries.

The chaotic scene was part of a long-running trend of violence at Trump rallies, where uncomfortable ethnic tensions have taken center stage in response to the candidate’s proposals to deport illegal immigrants en masse and temporarily ban foreign Muslims from the country. But unlike several violent eruptions earlier this spring, when the attacks were mostly carried out by Trump supporters against protesters, young anti-Trump protesters have been the assailants at several recent events.

Democrats and liberal activists said the acts were aberrations out of step with largely peaceful anti-Trump demonstrations.

“It’s deplorable, no matter who’s doing it,” Democratic presidential front-runner Hillary Clinton told CBS News Friday.

Clinton said in a separate interview that Trump shared some blame: “He created an environment in which it seemed to be acceptable for someone running for president to be inciting violence, to be encouraging his supporters, now we’re seeing people who are against him responding in kind,” Clinton said on CNN. “It should all stop. It is not acceptable.”

Trump and his supporters have dismissed the idea that he bears any responsibility for the assaults. At a Friday afternoon rally in Redding, Calif., which did not see any notable clashes, Trump said the assailants in San Jose were “thugs.”

“We wrapped up, everybody was cheering like crazy, and they walk out and they get accosted by a bunch of thugs burning the American flag,” Trump said, adding for emphasis: “And you know what? They are, they are thugs.”

Luis Miranda, communications director for the Democratic National Committee, stressed that the protesters were not connected to the party or Clinton’s campaign.

“Part of what we have to make clear is that these aren’t Democratic Party protests in any way,” Miranda said. “The vast majority of people who are protesting have done it peacefully and are protesting an ugly and divisive campaign.”

The images have been jarring: In April, in Costa Mesa, Calif., police clad in riot gear corralled protesters who vandalized police vehicles and harangued Trump supporters as they left a campaign event. The next day, in the Bay Area, protesters threw eggs and spat on police officers who formed a protective barricade around a venue where Trump was scheduled to speak.

The protests regularly feature oversize Mexican flags, presumably to protest the real estate mogul’s anti-immigrant rhetoric. Trump and his supporters have seized on the imagery to suggest that he is the target of an out-of-control and angry flank of the left that is hung up on identity politics.

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“What Trump’s most ardent supporters want is this clash of political civilizations,” said Republican strategist Kevin Madden, who says he will not vote for Trump in November. “They want . . . to show that a lot of these anti-Trump protesters who are waving Mexican flags and attacking Trump people, that those protesters are standing in their way of making America great again.”

The Trump campaign has wrongly suggested that the protests have been organized by the National Council of La Raza, an organization that promotes Hispanic equality.

Janet Murguía, president of the group, said Friday that the organization has not been involved in planning the protests. She said the confusion may come from the common use of the phrase “la raza,” or “the race,” by many Hispanic organizations.

Murguía condemned the violence and feared it would damage pro-Hispanic advocacy efforts. “I feel that it does undermine our overall objective in making sure that we can accomplish the results that we are fighting for,” she said.

Murguía also called on political leaders inside and outside of the Hispanic community to join in condemning the assaults.

“People have a right to be angry. We’re angry, too. But violence is never the answer,” she said. “We’re all now looking at this and thinking that we need to step up in different ways. I’m prepared to do that, and I know there will be others as well. In no way, shape or form should violence ever be the answer. It is incumbent upon us as leaders in this community to condemn this.”

Clashes have become common at Trump rallies, which were defined this spring by escalating tensions between protesters and supporters. As Trump’s chances of seizing the GOP nomination grew, mostly peaceful protesters flocked to his campaign events to denounce his anti-immigrant, anti-Muslim rhetoric.

High-profile incidents in Fayetteville, N.C., Louisville, Chicago and elsewhere featured a recurring pattern: Trump supporters, frustrated by interruptions, would punch, kick or drag out protesters.

Clinton and other Democrats have blamed Trump for setting a tone at campaign events that has made violence a regular feature. At times, Trump seemed to wink at the attacks by his supporters, promising in one instance that he would cover all legal costs incurred as a result and urging the crowds to break into chants of “Trump! Trump! Trump!” as protesters were hauled away.

“Donald Trump has inspired these protesters. This is not because of someone in the Democratic Party,” Democratic strategist Donna Brazile said Friday. “That kind of incendiary conversation and tone that he has set . . . that’s what’s inspiring this reaction, not the Democratic Party.”

Trump painted a different picture in Redding, saying the campaign has always treated protesters well.

“When we have a protester inside, which isn’t even very often, I say, ‘Be very gentle, please don’t hurt him,’ ” Trump said. “Take care of him. If he wants to shout — if he punches you in the face, smile, as your nose is pouring blood out of it. Be very, very nice.”

Sullivan reported from San Jose and Redding, Calif.