US President Donald Trump's longtime accounting firm must hand over eight years of his tax returns to New York prosecutors, a US appeals court has ruled.
The ruling by a unanimous three-judge panel of the New York-based 2nd US Circuit Court of Appeals backed the ability of prosecutors to enforce a subpoena for the returns against accounting firm Mazars LLP.
Mr Trump's lawyer Jay Sekulow said the Republican president will appeal the ruling to the US Supreme Court, whose 5-4 conservative majority includes two justices appointed by the president.
The office of Manhattan District Attorney Cyrus Vance, a Democrat, is seeking the returns as part of a criminal investigation into Mr Trump and his family real estate business. The scope of that probe is not publicly known.
The 2nd Circuit did not decide whether Trump is immune from being charged with a state crime while in office, as the president has argued.
However, it found that even if he is, the immunity could not stop Vance from getting the returns from a third party, or from prosecuting him once he leaves office.
It would "exact a heavy toll on our criminal justice system to prohibit a state from even investigating potential crimes committed by him for potential later prosecution," 2nd Circuit Chief Judge Robert Katzmann wrote in Monday's ruling.
