US President Donald Trump, his three oldest children and the Trump Organization have sued Deutsche Bank AG and Capital One Financial Corp to try to block them from responding to subpoenas issued by US congressional Democrats seeking financial records.

The lawsuit represents a new front in Trump's battle to stop the Democratic-controlled House of Representatives from probing the Republican president, his family, his businesses and his administration after Special Counsel Robert Mueller finished his inquiry into Russia's role in the 2016 election.

The complaint, filed on Monday night in federal court in Manhattan, also called quashing the subpoenas an urgent matter, saying that absent a court order Deutsche Bank planned to begin responding to its subpoena on May 6, and Capital One would feel obligated to begin responding by that date.

Deutsche Bank has long been one of the main banks for Trump's real estate empire, while the president's ties to Capital One were not immediately clear.

In the complaint, Trump, his adult children Donald Jr., Eric and Ivanka, and the Trump Organization accused House leaders of pursuing records for no legitimate or lawful purpose.

"The subpoenas were issued to harass President Donald J. Trump, to rummage through every aspect of his personal finances, his businesses, and the private information of the President and his family," the complaint said.

The lawsuit also accused Democratic leaders of hoping to "stumble upon something they can expose publicly and use as a political tool against the President."

Only the banks were named as defendants.

Deutsche Bank said it was "committed to providing appropriate information to all authorized investigations and will abide by a court order regarding such investigations."

Capital One was not immediately available for comment. Lawyers for the plaintiffs were not immediately available for comment.

DEFYING LAWMAKERS

Trump has aggressively sought to defy congressional oversight of his administration since Democrats took control of the House in January, building toward a major showdown between the executive and legislative branches of government testing the separation of powers spelled out in the US Constitution.

Representative Maxine Waters, who chairs the House Financial Services Committee, and Representative Adam Schiff, who chairs the House Intelligence Committee, said the lawsuit is part of Trump's "unprecedented stonewalling" of congressional oversight.

"As a private businessman, Trump routinely used his well-known litigiousness and the threat of lawsuits to intimidate others, but he will find that Congress will not be deterred from carrying out its constitutional responsibilities," they said in a statement.

Waters and Schiff said on April 15 their committees issued subpoenas to multiple financial institutions for information on Trump's finances.

Trump and his administration also are resisting other House subpoenas including requests for the president's personal and business tax returns, while the White House has sought to block current and former administration officials from cooperating with House investigators.

Trump, who is seeking re-election next year, has said he intends to defy efforts by congressional Democrats to look into his affairs, including possible dealings with Russia, adding that "we're fighting all the subpoenas" issued by the House.

In the complaint, the plaintiffs said House leaders ignored constitutional limits on Congress' power to investigate, and any probe needed to further some "legitimate legislative purpose" and could not be an end in itself.

They also said the subpoenas violated the plaintiffs' privacy rights, and the refusal of House committees to even provide copies of the subpoenas to the plaintiffs made it impossible to know, or negotiate, their scope or breadth.

Deutsche Bank stood almost alone in extending credit and managing money for Trump before he became president, as other banks avoided him because of his poor track record in paying back loans.

The German lender has extended a substantial amount of capital to the Trump Organization in the past decade, according to documents and media reports.

A 2017 financial disclosure form showed that Trump had at least $130 million of liabilities to Deutsche Bank. In March, the New York Times detailed other financial relationships, including more than $2 billion of property loans and private banking services.

Mueller's report detailed extensive contacts between Trump's campaign and Russia and described the campaign's expectation of benefiting from Moscow's actions, but did not conclude there was a criminal conspiracy.

Reuters