Lawyers for Donald Trump will ask a federal appeals court on Tuesday to block the Manhattan district attorney from accessing the US president's tax returns in connection with a criminal probe of his business practices.
Trump has spent a year fighting a grand jury subpoena from District Attorney Cyrus Vance to the president's longtime accounting firm Mazars USA, for eight years of Trump's personal and corporate returns.
The 2nd US Circuit Court of Appeals in Manhattan is scheduled at 10 am EDT (1400 GMT) to hear oral arguments on Trump's motion to delay the subpoena.
If the appeals court refuses a delay, Trump plans to ask the US Supreme Court to intervene.
In July, the Supreme Court refused to block the subpoena, rejecting Trump's claim of immunity from criminal probes while in the White House, but said he could raise other objections.
Trump, a Republican, has since argued that the "wildly overbroad" subpoena largely mirrored a subpoena from Congressional Democrats, and was issued in bad faith to target him.
Vance, a Democrat, began his probe after news that Trump's former lawyer Michael Cohen had paid pornographic film actress Stormy Daniels $130,000 to keep quiet before the 2016 election about claimed sexual encounters with Trump, which the president has denied.
The district attorney has said the litigation has effectively given Trump, who is seeking reelection on Nov. 3, the immunity he sought and which courts have rejected.
Vance has also said handing over the returns would not irreparably harm Trump, noting that grand jury proceedings are confidential and that every other US president starting with Jimmy Carter has publicly released his tax returns.