A federal judge on Wednesday blocked — for at least one day — enforcement of a grand jury subpoena demanding President Donald Trump's personal and corporate income tax returns as part of a criminal investigation by Manhattan District Attorney Cyrus Vance Jr.'s office.

But Judge Victor Marrero assured both Vance's prosecutors and Trump's lawyers that his ultimate decision on whether to allow the subpoena will not take "weeks or months."

Regardless of how he rules, Marrero's decision is guaranteed to be appealed by the losing side.

Marrero's temporary delay of the subpoena for eight years worth of Trump tax returns came at a hearing in U.S. District Court in Manhattan.

During that hearing prosecutors from Vance's office objected to a federal judge becoming involved in the question of the validity of a state grand jury subpoena. Those prosecutors also opposed a potential bid by federal prosecutors to intervene in the state case.

Trump's lawyers, on the other hand, argued for the temporary restraining order against the subpoena to Trump's accounting firm, Mazars USA, which the attorneys claim is not legally enforceable because of the president's supposedly unique immunity from criminal investigation.

One of those lawyers, William Consovoy, argued that both the Constitution and the Justice Department's Office of Legal Counsel say that the president cannot be criminally charged while in office.

However, Consovoy's claim has never been adjudicated by a court.

Solomon Shinerock, a prosecutor in Vance's office, told Marrero that Trump's lawyers "have no authority for the breathtaking breadth in their immunity" claim.

Vance is investigating potential violations of the law in how a hush-money payment to porn star Stormy Daniels was accounted for in business records by the Trump Organization, as well as possibly other issues.

Daniels, who says she had sex with Trump once in the mid-2000s, was paid $130,000 on the eve of the 2016 presidential election by Trump's then-personal lawyer and fixer Michael Cohen to keep her quiet about her allegation. Vance is also eyeing the $150,000 in hush money paid to Playboy model Karen McDougal by the publisher of the Trump-friendly supermarket tabloid The National Enquirer in the months leading up to the election.

Trump denies having had sex with McDougal or Daniels but personally reimbursed Cohen for the hush-money payout to Daniels, as did the Trump Organization.

Marrero told Vance's prosecutors and lawyers for Trump to take a day to discuss among themselves whether they can hash out a way for Trump's company to provide some of the documents sought that do not relate directly to Trump.

But if no agreement can be reached, Marrero left open the door to continue delaying enforcement of the subpoena for Trump's tax returns.

"I don't think it will be a fruitful discussion," said Casey Dunne, a prosecutor from Vance's office, who called the delay in enforcing the subpoena both "inappropriate" and "unnecessary."

"They win and we lose," Dunne griped to Marrero about the effect of his decision on prosecutors and Trump's lawyers.

"That is not what should happen today," the prosecutor said. "We ought to go home and do our work."

Marrero gave federal prosecutors until Monday to decide if they will formally seek to be heard in the case, which they have said in court papers raised "weighty constitutional issues."