An attorney for President Donald Trump, his children and the Trump Organization told a Manhattan-based appeals court on Friday that two House committees had taken on an improper law-enforcement function in issuing subpoenas for Trump family financial records.

In oral arguments that stretched on for about 90 minutes, Patrick Strawbridge of Consovoy McCarthy said the subpoenas of records from Deutsche Bank and Capital One were the "broadest possible subpoenas ever served that target a sitting president" and lacked any legitimate legislative purpose.

U.S. District Judge Edgardo Ramos of the Southern District of New York in May acknowledged that the subpoenas were "very broad," but rejected Trump's motion to enjoin compliance with them. Enforcement of that order, however, was stayed pending an appeal to the U.S. Court of Appeals for the Second Circuit.

A three-judge panel of the appeals court tackled questions of whether the courts had the ability to address the subpoenas' breadth and whether that raised separation-of-powers concerns, as the U.S. Justice Department argued in an amicus brief earlier in the week.

Douglas Letter, general counsel for the U.S. House of Representatives, said the subpoenas were part of a broader effort to investigate money laundering and foreign influence on the U.S. government.

A total of 10 subpoenas, he said, had been handed out in connection with the probe, including some that went to banks that had "absolutely nothing to do" with Trump and his family.

Letter said the subpoena served on Deutsche Bank touched on its lending to Trump but also could inform regulation of loan operations.

Letter said the bank had loaned Trump approximately $2 billion, and it would have been typical for a bank to request tax returns when making such a large loan.

It was clear from public reporting, Letter told the court, that for years Deutsche Bank had been willing to lend to Trump as a private businessman when almost no other financial institution would. The inquiry could inform Congress as it considered tougher regulation of bank lending to make sure "that doesn't happen."

Strawbridge, however, said the House committees had overstepped their legislative authority, and argued the true purpose of the subpoenas was to take up a law enforcement action against the president and his family.

Both sides said that talks over limiting the scope of the subpoenas had gone nowhere, but expressed a willingness to negotiate if the case were sent back to Ramos.

When pressed by Second Circuit Judge Jon A. Newman, Deutsche Bank attorney Raphael Prober, citing "contractual and statutory obligations," and said he could not confirm in open court whether the bank possessed Trump's tax returns, but said "significant" work had already been done in regard to the subpoenas.

The refusal kicked off a tense back-and-forth with the panel of judges, with Judge Peter Hall pointedly asking: "Do we have to go to court to seek an order?"

"I'm serious," he said.

Judge Debra Ann Livingston was the third member of the panel hearing the appeal.

The three-judge panel had two appointees of Republican presidents. Newman was appointed to the circuit by President Jimmy Carter. Hall and Livingston were each appointed by President George W. Bush.

Prober and Capital One attorney James Murphy said they would submit a filing to the court under seal, indicating what types of records they possessed.

The court did not indicate Friday when it planned to rule in the case.

Read More: