Trump rallies targeted by protesters in New M...

ANAHEIM, Calif. -- At least five people were detained Wednesday as police descended on protesters outside a Donald Trump rally in California.

The arrests came after police declared an unlawful assembly in an announcement from a helicopter and protesters thinned out.

Shouting matches had erupted between opponents and a few supporters of the presumptive Republican presidential nominee outside Anaheim Convention Center.

Earlier, demonstrators pummeled a Trump pinata, decapitating it outside the Anaheim Convention Center, where lines of law enforcement officers guarded entrances to Trump's speech.

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Some demonstrators with their faces covered by bandannas shouted expletives against the candidate, while others stood quietly with signs reading "migration is beautiful" and "we are not rapists."

Authorities were not informed of any plans for large-scale protests but boosted staffing for Trump's noon rally at the 7,500-seat arena as a precaution, said Anaheim police Sgt. Daron Wyatt.

Lizbeth Barrera of Anaheim is only 17 and can't vote this election. But the high school junior said she came out to protest against Trump because of his comments about Mexicans, among other reasons.

"We don't need a racist coming here and trying to convince people to vote for him," she said while holding a sign calling Trump a misogynist and bully.

Wearing a red "Make America Great Again" cap, Andrew Willingham, 24, said he has long disdained voting, and at first was wary of Trump, but was drawn in by his support for free markets.

"He's anti a lot of regulation, pro wall, which mean less minimum wages," he said. "I watched more and more of his stuff, and yeah, I fell in love."

An anti-Trump demonstrator protests as Orange County Sheriff officers stand watch outdoors before Republican U.S. Presidential candidate Donald Trump speaks at a campaign event in Anaheim, California U.S. May 25, 2016. REUTERS

Last month, anti-Trump demonstrators took to the streets outside a similar event in nearby Costa Mesa, damaging police cars and throwing bottles. At least 17 people were arrested.

The presumptive Republican presidential nominee has drawn thousands of ardent supporters to his events along with passionate critics of his plans to build a wall on the Mexican border and his comments about immigrants and Muslims.

Protesters seen from overhead in Anaheim, California, on Wednesday, May 25, 2016. CBS News

His appearances have generated protests in other states as well, most recently Tuesday night in Albuquerque, N.M., when demonstrators outside a rally clashed with police.

Demonstrators threw burning T-shirts, plastic bottles and other items at police officers, overturned trash cans and knocked down barricades.

Police responded by firing pepper spray and smoke grenades into the crowd outside the Albuquerque Convention Center.

Protesters overran barricades and clashed with police in riot gear. They also burned T-shirts and other items labeled with Trump's catchphrase, "Make America Great Again."

People were seen jumping on police cruisers causing damage to window shields, CBS Albuquerque affiliate KRQE-TV reported.

After hours of protests, police declared the protests an unlawful assembly, KRQE reported. Tensions reached a peak when demonstrators rushed the convention center's doors. Police barricaded the doors and protesters didn't get inside.

On Tuesday, Democratic Party leaders urged any protesters to act peacefully.

A message was sent to the Trump campaign seeking comment.