President Donald Trump and the Trump Organization have asked a U.S. judge to block a Congressional subpoena seeking business records from his longtime accounting firm Mazars USA LLP.

The subpoena is part of sweeping series of requests by Democratic lawmakers for financial records from the president’s company and Trump himself. Trump has refused to cooperate, and Monday’s lawsuit in Washington shifts what is certain to be an intense battle into the federal courts.

Private lawyers for the president said the House Oversight Committee is exceeding its authority by rummaging in Trump’s personal business records without a “legitimate legislative purpose.” Trump is suing in his individual capacity, and not as president.

“There is no possible legislation at the end of this tunnel,” Trump’s attorneys said in the complaint, accusing the committee led by Maryland Democrat Elijah Cummings of assuming the investigatory powers of the U.S. Justice Department.

“Its goal is to expose plaintiffs’ private financial information for the sake of exposure, with the hope that it will turn up something that Democrats can use as a political tool against the President now and in the 2020 election,” according to the complaint.

Mazars is required to comply with the subpoena by noon on April 29.

Cummings’s office had no immediate comment on the lawsuit.

Separately, House Democrats have asked the U.S. Treasury Department to turn over the past six years of Trump’s personal and business tax returns and related documents. The department is reviewing that request.

The case is Trump v. Cummings, 19-cv-1136, U.S. District Court, District of Columbia (Washington).