Protesters brawl at tax day rally in California

People participate in a Tax Day protest on April 15, 2017 in New York City. Activists in cities across the nation are marching today to call on President Donald Trump to release his tax returns. (Photo by Stephanie Keith/Getty Images)

Credit: Stephanie Keith

Credit: Stephanie Keith

People participate in a Tax Day protest on April 15, 2017 in New York City. Activists in cities across the nation are marching today to call on President Donald Trump to release his tax returns. (Photo by Stephanie Keith/Getty Images)

A “Patriot Day” rally turned violent when hundreds of supporters and detractors of President Donald Trump met Saturday.

A pro-Trump group had scheduled a rally at Martin Luther King Jr. Civic Center Park when a group opposed to the president said they were also going to meet at the park.

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Fistfights ended up breaking out between members from both groups during morning and afternoon protests, according to the Los Angeles Times.

Berkley police arrested 13 people and seized prohibited items, including a flagpole, knife, stun gun and helmets, according to KABC.

Thousands of people across the country took to the streets in protest, some asking the president to release his tax returns, others to show support of the Trump administration.