Protesters took to the streets at several rallies across the country as part of a "Tax March" protest demanding that President Donald Trump release his tax returns.
But Trump speculated that the protest was paid for.
"I did what was an almost an impossible thing to do for a Republican-easily won the Electoral College! Now Tax Returns are brought up again?" Trump tweeted. "Someone should look into who paid for the small organized rallies yesterday. The election is over!"
The April 15 protests saw thousands of people march in cities including New York, San Francisco, Washington D.C., and even Palm Beach, Florida, where the president spends a great deal of time at his Mar-a-Lago resort.
While many protesters took to the streets to protest Trump's policies as president, the protests were widely regarded as an organized effort to demand Trump release his tax returns, which he refused to do during the 2016 presidential campaign.
Presidential candidates are not required to release their tax returns to the public, but Trump became the first major party nominee to refuse the tradition in more than 30 years.
"How can we determine his conflicts of interest or stop him from receiving payments from foreign governments if he won’t show us the names of the people and corporations that he is in active partnership with all over the world?" said Democratic Rep. Jamie Raskin of Maryland, who appeared at the Washington rally, according to The New York Times.
Protesters in Palm Beach mocked the president outside of his resort home with signs that said, "Chicken-in-Chief."
"This is the closest we have come to making sure he sees us and hears us," said Debbie Wehking, a 66-year-old school principal from Miami. "He needs to show us his tax returns so that we can tell who’s influencing his decisions, who he owes money to, who he’s doing business with -- really so we can figure out whether he needs to be impeached."
The Tax March was organized by a group affiliated with MoveOn.org, the Working Families Party, Stand Up America, and several other Democrat-affiliated or leaning groups, according to the Tax March website.
"We are ordinary Americans, community organizers, advocates, and people from all walks of life and all backgrounds joining together to raise our voices and send a bold message to this administration: We care, and we will hold President Trump, his administration, and Congress accountable," the Tax March website states. "That means demanding transparency and that our president pay his fair share, just like the rest of us."