FRANKFURT (Reuters) - Germany’s largest bank has asked for more time to respond to a request from Democrats on a U.S. House of Representatives panel for details about U.S. President Donald Trump’s possible ties to Russia, a person familiar with the matter said on Monday. Deutsche Bank’s (DBKGn.DE) external counsel sent a letter dated Friday June 2 to the Democrats saying it needed additional time, the source told Reuters. The person spoke on condition of anonymity and declined to specify how much more time the bank’s counsel needed.  Several Democrats on the U.S. House Financial Services Committee sent a letter last month to John Cryan, chief executive officer of Deutsche Bank, seeking details that might show if Trump’s loans for his real estate business were backed by the Russian government. The letter asked for details of internal reviews of Trump’s transactions and gave the German bank until Friday to respond.  Deutsche Bank has declined to comment about any business dealings with Trump. The Republican president is mired in controversy over FBI and congressional probes into alleged Russian meddling in the 2016 U.S. presidential election and potential collusion between Moscow and the Trump campaign. Moscow has denied the allegations, and Trump has denied any collusion. Maxine Waters, Democrat representative for California and a member of the committee, was one of the original letter’s five signatories. She confirmed through a staff member on Monday that Deutsche did not provide “substantive responses to our requests”. “Congress remains in the dark on whether loans Deutsche Bank made to President Trump were guaranteed by the Russian government, or were in any way connected to Russia,” the Democrats wrote in their request to Deutsche Bank.  “It is critical that you provide this committee with the information necessary to assess the scope, findings and conclusions of your internal reviews,” they said. The Democrats cannot compel Deutsche Bank to hand over the information. The House committee has the power to subpoena the documents, but Republican committee members - who make up the majority of the panel - would have to cooperate. No Republicans have signed the document request. The congressional inquiry is also seeking information about a Russian “mirror trading” scheme that allowed $10 billion to flow out of Russia. In January, Deutsche Bank agreed to pay $630 million in fines for organizing the scheme that could have been used to launder money out of Russia. The trades involved, for example, buying Russian stocks in roubles for a client and selling the identical value of a security for U.S. dollars for a related customer. 