Donald Trump slammed the protesters at his recent California campaign events as "thugs and criminals," calling for police to dole out harsh punishments in a tweet early Saturday.

The "protesters" in California were thugs and criminals. Many are professionals. They should be dealt with strongly by law enforcement! — Donald J. Trump (@realDonaldTrump) April 30, 2016

Protests erupted Friday in Burlingame, where Trump spoke at California's GOP convention, with demonstrators shutting down streets and spilling out across the grounds of the Hyatt Regency hotel.

Video of the crowds showed a largely peaceful demonstration, though there were some pockets of aggressive protesters -- including some flag-burners and egg-throwers.

"No hate in our state," demonstrators chanted early in the day, with a few carrying Mexican flags in protest of Trump's anti-immigrant policies.

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According to Burlingame police, five people were arrested and one suffered a non-serious injury.

Because protesters surrounded the building, Trump, arriving with his Secret Service entourage, was forced to hop a low fence in order to enter the event space.

While speaking to the Republican convention, the billionaire made light of the situation, joking that he now knew what it felt like to cross the U.S.-Mexico border.

"We went under a fence and through a fence," Trump said Friday. "And oh boy, it felt like I was crossing the border, actually."

The protest was the second massive demonstration against Trump in just as many days.

During a large rally in Southern California Thursday night, violence broke out near the Orange County Fairgrounds while Trump spoke to an audience of approximately 18,000 supporters.

Two patrol cars were damaged, but no major injuries were reported.

On Thursday, Costa Mesa police arrested and released 17 people on charges of failing to disperse.