[Read Mr. Neal’s letter to the I.R.S. commissioner.]

The move by Mr. Neal came as other panels controlled by House Democrats were flexing their muscles. The House Judiciary Committee on Wednesday morning authorized its chairman to use a subpoena to try to force the Justice Department to give Congress a full copy of the special counsel’s report and all of the underlying evidence used to reach his conclusions on Russian interference in the 2016 election.

And the chairman of the House Oversight and Reform Committee said that he would soon ask for a vote on a subpoena of his own to compel Mazars USA, an accounting firm tied to the president, to produce a decade’s worth of Mr. Trump’s financial records.

“They have told us that they will provide the information pretty much when they have a subpoena,” the chairman, Representative Elijah E. Cummings of Maryland, told reporters. “And we’ll get them a subpoena.”

Unlike the chairmen of other committees, Mr. Neal is not relying on a subpoena or standard congressional processes. Instead, he is invoking an authority enshrined in the tax code granted only to the tax-writing committees in Congress that gives the chairmen of the House Ways and Means Committee and the Senate Finance Committee the power to request tax information on any filer.

Mr. Neal gave the agency until April 10 to comply with the request, and if he receives the information, he will then confidentially review it with his committee staff.