Thousands of protesters turned out Saturday in events across the country to demand President Trump release his full IRS returns, mostly large-but-peaceful events with several arrests reported in California.

That the events were held on the deadline for hundreds of millions of Americans to file their federal returns was largely coincidental. Their intent was to pressure Trump to release his tax documents and to help Trump opponents stake out their position ahead of the president’s pending tax reform plan.

“Today, across American we are taking the gloves off to say it’s time to knock off the tax rip-off,” Oregon Democratic Sen. Ron Wyden told a crowd of several hundred people gathered at the base of Capitol Hill.

“No more Cayman Islands tax breaks … no more Wall Street tax breaks,” he roared before the crowd marched several miles to the National Mall. “It’s time to knock off the secrecy Mr. President and release your own tax returns.”

TRUMP WON’T RELEASE TAX RETURNS

Twenty people were reportedly arrested when Trump protesters clashed with supporters in Berkley, Calif.

Several fights broke out and police in riot gear purportedly had to use pepper spray to subdue the crowd and confiscate fireworks that were set off at the event, according to The Mercury News.

Trump supporters were reportedly holding a free speech rally in a downtown park when they were met by opponents of the president and his policies, according to the newspaper.

About 150 protests were held across the county, largely organized by the group TaxMarch.org, whose executive committee includes a former Occupy Wall Street protester.

“The Tax March is a movement gaining momentum around the country to demand transparency and fairness from our commander in chief," the group says on its website.

That Trump will cave to the pressure and release his full tax returns appears unlikely, considering the president has said he won’t amid an ongoing IRS audit and the White House saying recently that he will not.

"Their whole message is they want to see the president's tax returns. I care far more about his policy than his tax returns," Trevor Dierdorff, El Paso County Republican Party chairman, told the Colorado Springs Gazette, ahead of a pro-Trump event there Saturday.

Two of the largest events are in Seattle, site of the World Trade Organization protests of the 1990s. In addition to the expected 25,000 marching in “Tax March Seattle,” as many as 7,000 Black Lives Matter activists plan to come out for their own rally focusing on Trump's tax returns.

Other events were held in Chicago, Florida and New York City.

Trump was met by protesters in south Florida, going from his golf club to his Mar-a-Lago resort home, as hundreds of people along his motorcade’s path demanded that he release his returns.

"Pay your taxes," several people, including some holding signs, yelled as they marched toward Mar-a-Lago.

One sign read, "Twinkle Twinkle Little Czar, Putin Put You Where You Are," further making clear that Trump critics think his returns will finally reveal conclusive ties to the Kremlin, as they suspect.

Others helping organize events Saturday included labor unions and activist groups such as MoveOn.org and Common Cause.

The idea for the march has its roots in the response to a January appearance by White House counselor Kellyanne Conway. Asked her thoughts on an online petition demanding Trump release his tax returns, Conway replied that the White House would not release his tax returns and the issue was of little concern to Americans.

“We litigated this all through the election. People didn't care. They voted for him,” she said on ABC News’ “This Week.”

The comments lit up social media and grassroots organizers began circulating plans for this weekend’s events.

Voters may be split on the tax return issue. An April Bloomberg/Morning Consult poll found 53 percent of voters want Trump to release his tax returns, and 51 percent believe his returns are either very or somewhat important to them.

Whether it resonates beyond Tax Day -- which is typically April 15, though the IRS is pushing the deadline to Tuesday -- is unclear. But Democrats in Congress continue to use tax returns as a wedge issue.

Senate Minority Leader Chuck Schumer, D-N.Y., said not releasing the returns would make getting bipartisan agreement on tax reform “much harder.”

In a much-hyped segment, MSNBC’s Rachel Maddow also recently aired a leaked copy of part of an old Trump tax return.

But it wasn't exactly damning. The files showed Trump paid $38 million in federal income tax in 2005 on more than $150 million. The effective rate of 25 percent was higher than the rate paid by former presidential candidate Bernie Sanders.