(CNN) House Ways and Means Committee Chairman Richard Neal has issued subpoenas for President Donald Trump's tax returns, the committee told CNN on Friday, an escalation in the fight for the President's personal financial records and the latest step this week in Democrats' battle for information from the Trump administration.

Neal sent subpoenas to both IRS Commissioner Charles Rettig and Treasury Secretary Steve Mnuchin. A Treasury spokesman confirmed to CNN it has received Neal's subpoena request.

Neal, who has unilateral subpoena power, took the step days after the Treasury Department formally denied Neal's request for six years of the President's personal and business tax returns earlier this week.

While Neal did not need a subpoena to eventually move to court, he issued the subpoenas on the advice of House counsel whom he consulted throughout the process about how to build the strongest legal case.

Unlike other requests for information coming from House Democrats, Neal is relying on a decades-old tax statute -- 6103 -- that says that the House Ways and Means chairman, Senate Finance Committee chairman or chief of staff of the Joint Committee on Taxation can request any individual's tax information in the course of their legislative business. Democrats have argued under that statute they have the ability to request Trump's tax returns even without a subpoena, but internal deliberations got Neal to the point where the advice was that a subpoena could bolster the case in court. The Democrats on Neal's committee have argued that they need access to the President's tax returns in order to understand how the IRS administers the presidential audit program even as Republicans and the Treasury Department have argued it is not a legitimate legislative purpose.

Read More