WATCH | Thousands gather to participate in the Tax March in the Nation's Capitol.
UPDATE 7:59 p.m. EST:
A CBS affiliate journalist identified as Neb Solomon was arrested during a Tax Day protest at President Trump's Las Vegas hotel, the Las Vegas Sun reported. Vegas police said a KLAS photojournalist was arrested and cited for trespassing and obstructing.
The afternoon protest at the Trump International Hotel near the Strip was attended by about 250. The rally largely remained peaceful with no injuries reported.
ORIGINAL STORY: Protests are sprouting up all across the United States ahead of Tax Day. Thousands nationwide gathered to demand that President Trump release his taxes -- a decades-old tradition in which most presidents and presidential nominees have voluntarily released their taxes to the public.
In the past, Trump initially has said he would release his taxes when after his routine audit is completed. That position was further reiterated by senior adviser Kellyanne Conway, who said that " POTUS is under audit and will not release until that is completed."
However, as stated by the Internal Revenue Service Commissioner John Koskinen, there is no law preventing Trump from releasing his taxes while he is under audit, Politico noted.
After Trump claimed that he has been audited every year, "twelve years or something like that," Koskinen said that scenario was rare, claiming that it would be unusual for anyone to be audited every year.
Trump also said that he wouldn't release his taxes because voters don't care.
"The only one that cares about my tax returns are the reporters," Trump said at a press conference. "I won."
The ambiguity surrounding Trump's taxes has inspired a movement. Organizers of the "Tax March" said that marches are taking place in about 150 cities, according to the Associated Press.
In Washington, D.C., however, the rally began at the U.S. Capitol, where Democratic lawmakers also called on Trump to stop the secrecy.
Sen. Ron Wyden called on Trump to 'knock off the secrecy." The Oregon lawmaker said people have "a basic right to know whether the president pays his fair share."
Rallies also occurred in places like New York and Mar-a-Lago, where the president is spending the weekend. In New York, celebrities joined the Tax Day demonstration. Comedian Sarah Silverman told the AP that she feels "beholden to be an active citizen."
WATCH | Hundreds of protesters gather in Palm Beach as part of nationwide tax demonstration.
In Palm Beach, Fla., hundreds of protesters marched, chanted and held signs that read, "Don the Con," ''Go back to New York," ''Show your taxes!" and "Show me the money!"