More than a dozen arrests were made Saturday afternoon during a rally in Berkeley, CA., where supporters of President Trump encountered protesters intent on disrupting the previously scheduled event.

Hundreds of Trump supporters had gathered at the Martin Luther King Jr. Civic Center Park in Downtown Berkeley, about two blocks from the UC Berkeley campus, for a “Patriots Day” rally. But they were soon met with many black-clad, face-covered counter-demonstrators waving red-and-black anarchy flags, and clashes ensued.

According to the Los Angeles Times, 250 police officers were deployed to the scene. Initially, the sides were separated by makeshift orange plastic barriers, but confrontations soon escalated.

Sixteen people were arrested, Officer Jennifer Coats of the Berkeley Police Department told the Times. Nine people were injured, with six taken to a hospital for treatment, including one stabbing victim, she said.

AJ Alegria, 31, of Sacramento, told the Times he came to Berkeley to help defend Trump supporters and was surrounded by a dozen protesters in black masks who he said attacked him with sticks and pepper spray.

“These people create violence all the time… somebody has to stand up to them,” said Alegria, who was injured in the fight and treated by Trump supporters who bandaged his head, washed off the pepper spray and gave him encouragement, saying, “You’ve earned your stripes, bro.”

Here are some of the prohibited items that have already removed from the park today. https://t.co/3qx3smYwgk pic.twitter.com/A70VCxFYEu — Berkeley Police (@berkeleypolice) April 15, 2017

Another Trump supporter, Ben Bergquam of Fresno, was also bloodied as the melee moved from the park up Center Street toward the UC Berkeley campus. He held a crumpled “Stop Liberal Intolerance” sign in his hand.

“I got hit in the back of the head with some sticks,” Bergquam told the San Francisco Chronicle as another activist wrapped gauze around his wound. “I don’t agree with everything Trump says, but I don’t agree with violence.”

With assistance from the Oakland Police Department, the Berkeley police fared better at keeping the peace than they did in February, when violent demonstrators set fires and destroyed more than $100,000 worth of property that forced the cancelation of a speech by then-Breitbart Tech editor Milo Yiannopoulos at UC Berkeley.

The Chronicle reported that several liberal groups long-planned to disrupt the pro-Trump rally with the intent to shut it down.

Defend the Bay, a group that advertises itself as against the self-described “alt-right,” suggested protesters bring food to share, along with a mask or other covering to conceal their identity from police.

Follow Samuel Chi on Twitter @ThePlayoffGuru.