President Donald Trump and his business filed suit against Democratic House Oversight Committee Chairman Elijah Cummings on Monday to block a subpoena sent last week seeking information about the president's finances.
In the complaint filed in Washington, D.C., federal court Monday morning, Trump's lawyers said that Democrats have "declared all-out political war" against him.
"Subpoenas are their weapon of choice," the filing states.
Last week, the House Oversight and Government Reform Committee subpoenaed Mazars, an accounting firm that Trump had used to prepare several years of financial statements, according to the lawmakers' document.
The subpoena requested a slew of financial documents and related materials from Trump, his trust, the Trump Organization, the Trump Corporation, Trump's holdings company, the Trump Foundation and the Trump International Hotel in Washington. Mazars told the committee that it would not be able to comply with demands for those documents without a subpoena, according to Cummings.
In a statement, Cummings said that Trump has a "long history of trying to use baseless lawsuits to attack his adversaries, but there is simply no valid legal basis to interfere with this duly authorized subpoena from Congress."
Cummings added: "This complaint reads more like political talking points than a reasoned legal brief, and it contains a litany of inaccurate information. The White House is engaged in unprecedented stonewalling on all fronts, and they have refused to produce a single document or witness to the Oversight Committee during this entire year."
Mazars and Peter Kenny, the Oversight Committee's chief investigative counsel, are also listed as defendants in the lawsuit.
Trump's lawyer in the lawsuit, William Consovoy, said in a statement that the attempt by Cummings' committee to "obtain years' worth of confidential information from their accountants lacks any legitimate legislative purpose, is an abuse of power, and is just another example of overreach by the president's political opponents."
The president's counsel, Jay Sekulow, told NBC News: "We will not allow Congressional Presidential harassment to go unanswered."
The White House did not immediately provide a statement to CNBC regarding the lawsuit.
Trump's lawyers argue that Cummings' subpoena lacks a "legitimate legislative purpose," and is therefore an invalid action for a congressional committee to take.
"With this subpoena, the Oversight Committee is instead assuming the powers of the Department of Justice," the complaint says.
"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."
The filing goes on to attack the credibility of the subpoena by connecting it to testimony given in February by Trump's former longtime personal attorney, Michael Cohen.
Cohen's damning testimony before the House Oversight Committee on Feb. 27 — in which Trump's former fixer called his ex-boss a "racist," a "cheat" and a "con man" — offered "one of the worst examples of the House Democrats' zeal to attack President Trump under the guise of investigations," Trump's lawyers said.
Cohen, who had previously pleaded guilty to lying to Congress about since-aborted plans to build a Trump Tower building in Moscow, is set to report to federal prison May 6.
A spokeswoman for Cohen's lawyer Lanny Davis, who is also mentioned in Trump's Monday morning court filing as "a political operative for the Democrat party," did not immediately respond to CNBC's request for comment.
Democrats have called on Trump to disclose a variety of financial documents since the 2016 election — especially his tax returns, which presidential candidates have traditionally released voluntarily but which Trump refused to share.
House Ways and Means Committee Chairman Richard Neal, D-Mass., formally requested that the Internal Revenue Service hand over years of Trump's returns. Earlier this month, Neal set a Tuesday deadline for IRS Commissioner Charles Rettig to deliver six years of Trump's personal and business tax returns.
Meanwhile, federal prosecutors in New York are digging into the Trump campaign's finances — an investigation stemming at least in part from Cohen's admission that he committed campaign finance violations by facilitating hush-money payments to two women during the 2016 election who claimed they had affairs with Trump years earlier.
Trump has denied having sex with either woman and also has denied directing Cohen to pay them. Cohen, however, says Trump directed him to make the payments.