Treasury Secretary Steven Mnuchin said Wednesday that he has never had any conversations with President Donald Trump "or anyone in the White House" about providing Trump's tax returns to Congress.

"I've had no conversations ever with the president or anyone in the White House about delivering the president's tax returns to Congress," Mnuchin said during a hearing before the House Financial Services Committee.

Trump has refused to make his returns public, breaking with the practice followed by every American president since Richard Nixon.

Democrats have sought access to the president's tax returns through other means. In Congress, House Democrats have demanded access to Trump's tax documents under a 1924 law that dictates that the Treasury secretary "shall furnish" them if requested by lawmakers.

But Mnuchin has so far declined to comply, and has said that the question will likely be resolved by the courts. On Friday, Mnuchin defied a subpoena from the House Ways and Means Committee for six years of the president's returns on the basis that the request lacked "a legitimate legislative purpose."

A confidential draft IRS memorandum, the findings of which were made public by The Washington Post on Tuesday evening, seemed to contradict Mnuchin's reasoning.

That memo says that the law "does not allow the Secretary to exercise discretion" regarding the disclosure of tax returns, and argues that the "only basis [for] the agency's refusal to comply with a committee's subpoena would be the invocation of the doctrine of executive privilege."

Trump has not invoked executive privilege in the matter.

Mnuchin said during Wednesday's hearing that he believed the memo was "addressing a different issue" and warned about Democrats "weaponizing" the IRS.

"I became aware of that memo when we got an inquiry from The Washington Post," Mnuchin said. He added later, "We are trying to find out who wrote the memo, where it came from, when it was, and why it wasn't distributed."

"I don't know how it got to The Washington Post," he said. "It would have been more interesting if it got to me or the [commissioner of the IRS Charles Rettig] for review."

Rep. Richard Neal, D-Mass., who chairs the Ways and Means Committee, has said a lawsuit seeking to enforce the subpoena could come as soon as this week.