FRANKFURT/WASHINGTON (Reuters) - A U.S. federal investigator probing alleged Russian interference in the 2016 U.S. presidential election asked Deutsche Bank DBKGn.DE for data on accounts held by President Donald Trump and his family, a person close to the matter said on Tuesday, but Trump's lawyer denied any such subpoena had been issued.

Germany’s largest bank received a subpoena from Special Counsel Robert Mueller several weeks ago to provide information on certain money and credit transactions, the person said, without giving details, adding that key documents had been handed over in the meantime.

Deutsche Bank has lent the Trump Organization hundreds of millions of dollars for real estate ventures and is one of the few major lenders that has given large amounts of credit to Trump in the past decade. A string of bankruptcies at his hotel and casino businesses during the 1990s made most of Wall Street wary of extending him credit.

Mueller is investigating alleged Russian attempts to influence the election, and potential collusion by Trump aides. Russia has denied U.S. intelligence agencies’ conclusion that it meddled in the election and Trump has said there was no collusion with Moscow.

Jay Sekulow, one of Trump’s personal lawyers, said Deutsche Bank has not received any subpoena for financial records relating to the president as part of Mueller’s probe.

“We have confirmed that the news reports that the Special Counsel had subpoenaed financial records relating to the president are false,” Sekulow told Reuters in a statement. “No subpoena has been issued or received. We have confirmed this with the bank and other sources.”

He later said the bank in question was Deutsche Bank. A spokesman for Mueller declined to comment.

A Deutsche Bank spokesman in New York had no immediate comment beyond the statement the bank issued earlier on Tuesday which said the bank takes “its legal obligations seriously and remains committed to cooperating with authorized investigations into this matter.”

A U.S. official with knowledge of Mueller’s probe said one reason for the subpoenas was to find out whether Deutsche Bank may have sold some of Trump’s mortgage or other loans to Russian state development bank VEB or other Russian banks that now are under U.S. and European Union sanctions.

VEB, as well as the Russian Agricultural Bank and Gazprombank GZPRI.MM did not immediately reply to emailed requests for comment.

"No one from the VTB Group VTBR.MM representatives has received a subpoena because there are absolutely no grounds for it," a bank representative said in response to a request from Reuters. "Deutsche Bank did not contact us regarding people connected with the Trump administration."

"We would not comment on the existence of any such request, had one been received," responded a representative of Sberbank SBER.MM.

Holding Trump debt, particularly if some of it was or is coming due, could potentially give Russian banks some leverage over Trump, especially if they are state-owned, said a second U.S. official familiar with Russian intelligence methods.

“One obvious question is why Trump and those around him expressed interest in improving relations with Russia as a top foreign policy priority, and whether or not any personal considerations played any part in that,” the second official said, speaking on the condition of anonymity.

A source close to Deutsche Bank said the bank had run checks on Trump’s financial dealings with Russia.

During his election campaign, Trump said he would seek to improve ties with Russian President Vladimir Putin, which were strained during President Barack Obama’s administration.

The subpoena was earlier reported by German daily Handelsblatt.

Special Counsel Robert Mueller departs after briefing the U.S. House Intelligence Committee on his investigation of potential collusion between Russia and the Trump campaign on Capitol Hill in Washington, U.S., June 20, 2017. REUTERS/Aaron P. Bernstein

FINANCES A RED LINE

During a photo opportunity with senators at the White House on Tuesday, Trump declined to answer shouted questions from reporters about whether Mueller had crossed a line by asking Deutsche Bank for information.

In a July 9 interview with the New York Times, Trump said Mueller should not extend his investigation into Trump’s finances if they were not directly related to the Russia accusations.

Asked if delving into his and his family’s finances unrelated to the Russia probe would cross a red line, Trump replied, “I would say yeah. I would say yes.”

Deutsche Bank earlier this year rebuffed efforts by Democratic U.S. lawmakers to get more information on its dealings with Trump as well as any information it may have about whether the Republican, his family or advisers had financial backing from Russia.

Trump had liabilities of at least $130 million to Deutsche Bank Trust Company Americas, a unit of the German bank, according to a federal financial disclosure form released in June by the U.S. Office of Government Ethics.

The Deutsche debts include a loan exceeding $50 million for the Old Post Office, a historic property he redeveloped in downtown Washington, mortgages worth more than $55 million on a golf course in Florida, and a $25 million-plus loan on a Trump hotel and condominium in Chicago, the disclosure shows.

All of those loans were taken out in 2012 and will mature in 2023 and 2024, according to the disclosure.

Trump and Deutsche Bank have not always been on good terms. Trump sued the bank and other lenders in 2008, demanding $3 billion in damages, claiming they broke agreements in the construction and financing of a Chicago hotel.

Deutsche Bank countersued and the two sides eventually settled.

Internal Deutsche Bank documents seen by Reuters feature the names of Trump’s former campaign manager Paul Manafort and his wife, Kathleen, in a series of client profiles. But it was not immediately clear what their relationship with the bank is or had been.

According to a person familiar with the matter who spoke on the condition of anonymity, Manafort and his wife do not have Deutsche Bank accounts.

The bank declined to comment on whether Manafort is or has ever been a client.

A spokesman for Manafort declined to comment.

In October, Manafort pleaded not guilty to charges including conspiracy to launder money and conspiracy against the United States. The charges were brought as part of Mueller’s investigation.