Several protesters were arrested outside Donald Trump’s campaign rally Wednesday in Southern California, but a heavy police presence helped deter violent demonstrations like those that occurred the night before at a rally in New Mexico.

Police in Anaheim, Calif., where Wednesday's event was held, had warned anti-Trump protesters about clashing with law enforcement. 

Anaheim Police said 14 people were arrested Wednesday. 

About 100 officers, including some in riot gear, lined up in preparation outside the Anaheim Convention Center, including dozens on horses -- a day after New Mexico protesters burned flags and pelted officers in riot gear with bottles and other debris.

After the Anaheim rally, officers stopped clashes among anti-Trump protesters and Trump supporters while mounted police formed a line and pushed protesters, including some wearing masks and throwing rocks, away from the center.

During the rally, there were several shouting matches between the supporters and protesters and event-goers thrashed a Trump-like piñata. A few protesters also were escorted from the building.

“Get them out of here,” said Trump, his usual response to being disrupted by protesters. “Out, out, out.”  

Earlier in the day, Anaheim Police Chief Raul Quezada warned that violence would not be tolerated.  

"While we recognize and respect the First Amendment rights of all individuals … we will not tolerate violence or disobedience of the law during the upcoming rally," he said. "We are prepared to take swift and decisive enforcement action should it become necessary."

About 150 protesters attended the midday event, roughly equal to the number of journalists who attended.

Even before the clashes overnight in New Mexico, several previous Trump events have been marred by angry protests.

In March, the Trump campaign was forced to cancel a rally at the University of Illinois at Chicago, citing “growing safety concerns.”

Hundreds of protesters responded to requests by social activists and other Trump detractors' request to disrupt the event. The cancellation sparked several small scuffles between pro- and anti-Trump groups inside and outside the event.

But the New Mexico incident ended a stretch of relative calm, which appeared to start near the time Trump became the party’s presumptive presidential nominee in early May.

Protesters in the unruly spectacle threw burning T-shirts, plastic bottles and other items at police officers, injuring several, and toppled trash cans and barricades.

Police, including at least some in riot gear, responded by firing pepper spray and smoke grenades into the crowd outside the Albuquerque Convention Center. At least one person was arrested, police said.

Inside the rally, protesters shouted at Trump, resisted being removed by security officers and wave banners including ones that read "Trump is Fascist" and "We've heard enough."

Trump told the officers to remove the protesters and mocking their actions, telling them to "Go home to mommy."

On Wednesday, he tweeted that the protesters were “thugs who were flying the Mexican flag. The rally inside was big and beautiful, but outside, criminals!"

The protesters burned T-shirts and other items labeled with Trump's catchphrase, "Make America Great Again."

The violence in New Mexico prompted security concerns elsewhere.

Police in Bismarck, N.D., said Wednesday they would dedicate about a quarter of their force for security when Trump heads to the state Thursday.

Trump will be the keynote speaker at the Williston Basin Petroleum Conference and Expo, with about 7,000 people expected to attend.

Fox News' Lee Ross and The Associated Press contributed to this report.