President Donald Trump's lawyers on Tuesday asked for more time before his personal accounting firm must comply with a Manhattan Supreme Court grand jury subpoena seeking his tax returns.

In what's expected to be the final substantive filing before a showdown between Trump lawyers and New York County District Attorney Cyrus Vance Jr. in the Southern District of New York on Wednesday morning, the president's legal team said a stay agreed to by Vance—which expires Wednesday—won't give the federal court enough time to adequately consider whether the subpoenas may be enforced.

The subpoenas were issued Aug. 29 and first reported by the New York Times on Sept. 16.

Trump lawyers turned last week to the Southern District of New York federal court to sue Vance and the accounting firm, Mazars USA, in federal court, contesting the subpoena and describing it as a politically motivated attack.

Vance agreed to stay enforcement of the subpoena until Wednesday afternoon, shortly after the hearing, but Trump's lawyers argued that won't give the district court enough time to consider the case.

Instead, Trump's lawyers, in a brief submitted by William Consovoy of Consovoy McCarthy, asked U.S. Senior District Judge Victor Marrero of the Southern District of New York to extend Mazars' deadline to comply until seven days after he has ruled on Trump's motion for a preliminary injunction.

The general counsel for Vance's office, Carey Dunne, argued Monday that Trump should have filed suit in state court, since he was contesting a state subpoena.

Trump's lawyers replied that, while the 1971 U.S. Supreme Court decision Younger v. Harris found that federal courts should usually avoid interference with state criminal prosecutions, "that ship has already sailed when a state is pursuing criminal process against a sitting president."

Trump faces permanent harm if his tax returns are released, his lawyers argued, because they are his confidential financial information and because he has the right to judicial review of the constitutional claims raised in this case. They rejected assurances from Vance about the confidentiality of grand jury materials, noting that New York could change its laws at any time.

The hearing in the case is set for 9:30 a.m. Wednesday.