Protests have been taking place in more than 150 locations across the United States to call on President Donald Trump to release his tax returns.
Mr Trump broke a long-held tradition by not releasing his paperwork during his presidential campaign.
His critics want to know who he has been dealing with and if there are any conflicts of interest.
At least 21 people were arrested in Berkeley, California, in clashes between Trump opponents and supporters.
There is no law requiring presidents to release their tax returns, but Mr Trump has found himself under public pressure since some information from a 2005 tax return was leaked to the media last month.
April 15, the traditional Day of Dread for US taxpayers, is the backdrop on Saturday for marches and rallies in Washington and nearly 150 other cities around the country aimed at pressuring President Donald Trump to release his federal tax returns. Marches also took place in Europe, Japan and New Zealand.
As a candidate and as president, Trump has steadfastly refused to release his tax returns, citing an ongoing audit by the Internal Revenue Service. In September, he said, “I don’t think anybody cares, except some members of the press.”