IRS Commissioner Charles Rettig told a U.S. House subcommittee Tuesday that he's talked to Treasury Secretary Steven Mnuchin about how to respond to a request by Ways and Means Committee Chairman Richard Neal to turn over six years of President Donald Trump's tax returns by Wednesday.

Rettig refused to say, however, whether he will ultimately make the decision about releasing those tax records or leave that task to Mnuchin. Neal, who says he has authority to see the president's personal and business returns under a Tax Code provision, directed his letter to Rettig, formerly a Beverly Hills tax lawyer before he jumped to the Trump administration.

“We are a bureau of the United States Treasury, and we are supervised by Treasury,” Rettig told the Subcommittee on Financial Services and General Government. “And so we did receive the letter. We're looking into it and expect to respond.”

Rettig said no one at the Internal Revenue Service “to my knowledge” has been in contact with the White House about the president's tax returns and that Mnuchin did not direct him to make any decision about Neal's request.

“Did [Mnuchin] suggest he was going to make the decision for you?” asked subcommittee Chairman Mike Quigley, D-Illinois.

“There was a discussion about—and that's what I say when we're working on it,” Rettig said. “There was a discussion about who was going to handle the response.”

“And what did the treasury secretary say?” Quigley asked.

“There was no conclusion on that,” Rettig said.

The Washington Post reported Tuesday that Treasury Department lawyers had talked with the White House about Trump's tax returns. Mnuchin reportedly told a House appropriations committee that the “communications between our legal department and the White House general counsel was informational.”

Access to Trump's tax returns has quickly become the IRS commissioner's biggest issue during his short tenure. Rettig, a longtime tax lawyer at Hochman, Salkin, Rettig, Toscher & Perez, took office in October.

Rettig was questioned during his confirmation process about a 2016 article he wrote defending then-candidate Donald Trump's refusal to release any tax returns because, he said, he was under audit. Rettig pledged during the confirmation hearing that he would maintain the tax agency's political independence.

Trump's attorneys have argued that the IRS cannot legally release the president's returns, and Republicans have accused Neal and other Democrats of trying to use private tax information for political gain.

“It just seems like we have a chairman and potentially a party that's attempting to weaponize the IRS for political gain,” said subcommittee ranking member Garret Graves of Louisiana.