The Manhattan District Attorney's Office is seeking the financial records as part of a probe into hush money payments to two women claiming affairs with Trump.
The Justice Department is joining President Donald Trump in his legal battle to block the release of his tax returns to state prosecutors investigating the Trump Organization, according to court papers filed Wednesday.
Manhattan District Attorney Cyrus Vance is seeking eight years of Trump's personal and corporate tax returns as part of a criminal investigation into the Trump Organization over hush money payments made to two women who have alleged affairs with Trump before he became president.
The president's lawyers filed a lawsuit in federal court late last month seeking to block the subpoena. The suit says Vance isn't entitled to the returns and a sitting president cannot be criminally investigated.
Trump also named his accountant Mazars USA as a defendant in the suit as part of his bid to prevent his financial records from being turned over to Vance's office.
The case took a turn last week when federal prosecutors filed court papers saying they were weighing whether to intervene in the president's suit.
In the Wednesday court filing, Justice Department special counsel Joshua Gardner argues that the suit has significant implications for the country and the tax returns should not be released until it's resolved.
"The President's complaint raises a number of significant constitutional issues that potentially implicate important interests of the United States," the court filing says.
The Justice Department requests that the judge put the subpoena process on hold to allow it to prepare briefs in the case.
Vance's office declined to comment and indicated it will respond in court.
Trump's lawyers have argued that the Constitution immunizes the president from criminal investigations. Vance's office rejected that argument and questioned whether federal prosecutors should be allowed to join the lawsuit at the eleventh hour.
Vance's office is probing hush money payments made during the 2016 election to adult film star Stormy Daniels and ex-Playboy model Karen McDougal, both of whom have alleged affairs with Trump. The president has denied the affairs.
The Trump Organization has already provided 3,376 pages of records to the D.A.'s subpoenas and inquiries into the hush money payments, court documents say, but no tax records.