Supporters at a Saturday rally in favour of U.S. President Donald Trump clashed with counter-protesters in the famously left-leaning city of Berkeley, Calif.

At a park in Berkeley, across the bay from San Francisco, protesters from both sides struck their opponents over the head with wooden sticks. Trump supporters fired pepper spray at counter-protesters as police in riot gear stood at a distance.

Some in the pro-Trump crowd, holding U.S. flags, faced off against black-clad opponents. An elderly Trump supporter was struck in the head and kicked on the ground.

Here we go again. Not the first fight that's broken out at the <a href="https://twitter.com/hashtag/trump?src=hash">#trump</a> rally in <a href="https://twitter.com/hashtag/Berkeley?src=hash">#Berkeley</a>. <a href="https://t.co/ZPW6QbI5S1">pic.twitter.com/ZPW6QbI5S1</a> —@lizziejohnsonnn

Berkeley police say 10 people were arrested and seven people were injured, though none needed nor wanted to go to a hospital

The police department said five people were arrested for battery, four for assault with a deadly weapon and one for resisting arrest.

The department said officers confiscated a dagger, metal pipes, bats, pieces of lumber and bricks.

Counter-demonstrators and supporters of Trump fight for a U.S. flag in Berkeley. Protesters struck their opponents over the head with wooden sticks, and Trump supporters fired pepper spray at counter-protesters as police in riot gear stood at a distance. (Stephen Lam/Reuters)

Multiple arrests across the U.S.

Six people protesting the rally in St. Paul, Minn., were arrested on felony riot charges after they lit fireworks inside the Minnesota state capitol and fled, police said. About 400 people attended the event, and about 50 showed up to protest it.

In Nashville, two people were arrested as protesters clashed with Trump supporters at the Tennessee Capitol.

Capitol police officers take an anti-Trump protester to the ground before taking him into custody at the State Capitol on Saturday in St. Paul, Minn. (David Joles/Star Tribune via AP)

In Olympia, Wash., the state patrol says four demonstrators were arrested at a rally in support of Trump, KOMO-TV reported. Authorities did not say if the people arrested were pro-Trump or anti-Trump. The station reports that the demonstrators are accused of assaulting a police officer.

Near Mar-a-Lago, the Palm Beach Post reported that people on both sides exchanged profanity. Trump's motorcade briefly stopped so he could wave at supporters.

John Pope, left, expresses his disagreement with Trump supporters near the president's Mar-a-Lago resort home on Saturday in West Palm Beach, Fla. (Joe Raedle/Getty Images)

'We need to support our president'

Organizers of the so-called Spirit of America rallies in at least 28 of the country's 50 states had said they expected smaller turnouts than the huge crowds of anti-Trump protesters who clogged the streets of Washington and other cities the day after Trump's inauguration on Jan. 20.

Their predictions appeared to be correct, as they were on Monday when similar rallies were held. In many towns and cities, the rallies drew only a few hundred people, and some were at risk of being outnumbered by small groups of anti-Trump demonstrators who gathered to shout against the rallies.

Trump supporters march east on the bike path along Metro Parkway in Clinton Township, Mich., on Saturday. (Detroit News via AP)

"People feel like they can't let their foot off the gas and we need to support our president," said Meshawn Maddock, one of the organizers of a pro-Trump rally of about 200 people in Lansing outside the Michigan State Capitol building.

"How can anyone be disappointed with bringing back jobs? And he promised he would secure our borders, and that's exactly what he's doing."

Brandon Blanchard, 24, among a small group of anti-Trump protesters, said he had come in support of immigrants, Muslims and transgender people, groups that have been negatively targeted by Trump's rhetoric or policies.

Trump supporters march from the National Mall to the White House during a rally organized by the North Carolina-based group Gays for Trump on Saturday. (Manuel Balce Ceneta/Associated Press)

"I feel that every American that voted for Trump has been deceived. Many campaign promises have already been broken," Blanchard said.

In Washington, more than 150 Trump supporters marched a short distance from the Washington Monument to Lafayette Square in front of the White House to show their backing for the embattled president, who was in Florida for the weekend.

During rallies before and after the march, speakers echoed many of Trump's pronouncements about illegal immigration, the Islamic State, Obamacare and "fake news."

Demonstrators gather near the White House on Saturday. Supporters gathered in cities nationwide to voice support for Trump. (Aaron P. Bernstein/Getty Images)

"There are a lot of angry groups protesting, and we thought it was important to show our support," said Peter Boykin, president of Gays for Trump, who helped organize the Washington rally.

During the rally, a small group of anti-Trump protesters stood nearby holding placards with slogans such as "Resist Hate" and "Make Racists Afraid."

Some of them occasionally shouted at the speakers near the Washington Monument, prompting about a dozen police to form a line separating the protesters from the Trump supporters.

Trump supporters gather at Neshaminy State Park in Bensalem, Pa., on Saturday. (Mark Makela/Reuters)

In Denver, several dozen people held pro-Trump signs at the top of the steps of the Colorado State Capitol building, according to video footage streamed online.

Two lines of police below them looked out on a small crowd of people protesting the rally at the bottom of the steps.

"No hate! No fear! Immigrants are welcome here!" the anti-Trump protesters shouted up the steps, along with obscene anti-Trump slogans.

A supporter of U.S. President Donald Trump wears a campaign hat during a 'People 4 Trump' rally at Neshaminy State Park in Bensalem, Pa., on Saturday. (Mark Makela/Reuters)

The pro-Trump demonstrators were quieter, holding up Trump signs as they milled about the steps, the video showed.

In the nation's capital, more than a hundred people rallied near the Washington Monument before the march to Lafayette Square.

"He does not hate Latinos, he does not hate Hispanics, he does not hate Mexicans," a woman who described herself as a Mexican-American supporter of Trump said, addressing the crowd from a small stage. "He's put his life at risk for us."