House Oversight Committee Chairman Elijah Cummings, D-Md., has requested a decade's worth of President Donald Trump's financial records from an accounting firm that prepared several years of financial statements for Trump, according to a letter Cummings sent on March 20, but which was only released on Wednesday.

The move represents an escalation of congressional Democrats' longstanding interest in obtaining Trump's financial records. Trump refused to release his tax returns during his 2016 presidential campaign, making him the first major party nominee not to do so in three decades.

Cummings' letter is addressed to Victor Wahba, CEO of Mazars USA, a New York-based accounting firm that prepared statements of financial condition for Trump covering 2011, 2012 and 2013, that were prepared to help the real estate mogul secure a loan. Michael Cohen, the president's former personal lawyer, turned those documents over to the committee this year ahead of his February 27 testimony.

Cohen provided the documents as evidence to support his claim that Trump had submitted false financial statements to Deutsche Bank in order to get financing to buy the Buffalo Bills NFL team. Cohen also alleged that Trump submitted false information to an insurance company, and that he may have deflated the value of his real estate assets in order to lower his tax bill.

The documents signed by Mazars, Cummings wrote to Wahba, "raise questions about the President's representations of his financial affairs on these forms and on other disclosures, particularly relating to the President's debts."

Specifically, Cummings questioned why the financial statements that Mazars had prepared for Trump included:

A stated increase of $4 billion to Trump's total net worth between 2012 and 2013 that was attributed to "brand value," a metric that did not appear on either the 2011 or 2012 financial statements the committee received from Cohen. A line in the 2012 financial statement which said that two of Trump's biggest debts, related to Trump Tower properties in Las Vegas and in Chicago, were being omitted from that year's tabulation. A line in both the 2011 and 2012 financial statements which stated that Trump had determined the value that his personal reputation brought to "real estate licensing developments" that were still being negotiated was $110 million in 2011 and $85 million the following year. An interest rate in 2012 for a $125 million loan Trump received from Deutsche Bank that was significantly higher than the interest rate Trump later reported paying on that same debt in his 2015 federal financial disclosure forms, which Trump submitted to the Federal Election Commission.

Wahba was given until April 3 to furnish the requested documents to the committee, and it was unclear Wednesday how Mazars plans to respond to Cummings request. Reached for comment, a spokeswoman for the firm told CNBC, "Mazars believes strongly in the ethical and professional rules and regulations that govern our industry, our work and our client interactions. As a matter of firm policy and professional rules we do not comment on the work we conduct for our clients."

Earlier in the day Wednesday, two of the Oversight Committee's most outspoken Republicans, Ohio Rep. Jim Jordan and North Carolina Rep. Mark Meadows, had released their own letter to Cummings, in which they claimed that the document request "appears to depart from responsible and legitimate oversight," and was meant "solely to embarrass President Trump and to advance the relentless Democrat attacks upon the Trump administration."

Cummings dismissed the criticism, telling Politico, "If they had their way, the committee would just close up shop for the next two years, but that is not what the American people elected us to do."