NEW YORK - President Donald Trump's longtime accounting firm must hand over eight years of his tax returns to New York prosecutors, a U.S. appeals court ruled Monday in the latest setback for Trump in his tenacious efforts to keep his finances secret.

The ruling by the New York-based 2nd U.S. Circuit Court of Appeals backed the ability of prosecutors to enforce a subpoena for the returns against accounting firm Mazars LLP. With the Republican president due to appeal, the ruling sets the stage for an expected showdown at the U.S. Supreme Court, whose 5-4 conservative majority includes two justices appointed by Trump.

House Democrat Issues Subpoenas for Trump Tax Returns A top House Democrat on Friday issued subpoenas for six years of President Donald Trump's tax returns, giving Treasury Secretary Steven Mnuchin and IRS Commissioner Charles Rettig a deadline of next Friday to deliver them. Ways and Means Committee Chairman Richard Neal, D-Mass., issued the subpoenas days after Mnuchin refused to comply with demands to turn over Trump's returns. A top House Democrat on Friday issued subpoenas for six years of President Donald Trump's tax returns, giving Treasury Secretary Steven Mnuchin and IRS Commissioner Charles Rettig a deadline of next Friday to deliver them. Ways and Means Committee Chairman Richard Neal, D-Mass., issued the subpoenas days after Mnuchin refused to comply with demands to turn over Trump's returns.

The office of Manhattan District Attorney Cyrus Vance, a Democrat, is seeking the returns as part of a criminal probe into Trump and his family real estate business. The scope of that probe is not publicly known.

Vance's office has agreed not to enforce the subpoena while Trump petitions the Supreme Court. Under the agreement, Trump has 10 business days to file the petition. Trump, who built a real estate empire with his New York-based business before becoming president, also faces an impeachment inquiry in the Democratic-led U.S. House of Representatives.