Rep. Elijah Cummings, expected to serve as next chairman of Oversight, seeks documents from Trump Organization, White House

The incoming chairman of the House Oversight Committee is demanding documents.

House Democrats, eager to conduct oversight of the executive branch, have put the Trump administration on notice.

Rep. Elijah Cummings, D-Maryland, who is expected to serve as the next chairman of the powerful House Oversight Committee, issued more than 50 letters to the White House, federal agencies and the Trump Organization requesting documents and records on a range of issues that Democrats plan to investigate in the next Congress. It's the opening salvo in what could be a contentious series of confrontations between the Trump administration and Democrats, who have pledged to investigate the Trump Organization and the president's personal finances.

The letters included several bipartisan requests from congressional Republicans and Democrats that the administration had not fully complied with, he said.

"Many of these requests were bipartisan, and some are now more than a year old," Cummings said in a statement. "As Democrats prepare to take the reins in Congress, we are insisting -- as a basic first step -- that the Trump Administration and others comply with these Republican requests.”

Cummings, who has asked for responses to the requests by Jan. 11th, has sketched out an ambitious oversight agenda of Trump administration actions and controversies. They include, the family separation policy at the U.S.-Mexico border, the federal response to hurricanes in Puerto Rico, the security clearance process at the White House, cabinet secretaries' travel and ethical questions about foreign payments to the Trump Organization.

Democrats have questioned the use of private email by some White House employees in light of Trump's campaign criticism of Hillary Clinton's use of private email when she served as secretary of State. A lawyer for Trump previously told ABC News that the email addresses were only used for scheduling purposes and were not used to transmit classified information.

In another letter to the Trump Organization and Sheri Dillon, a Trump attorney, Cummings requested details about the system the president announced in Jan. 2017, before taking office, to avoid conflicts of interest and how the Trump Organization has identified payments from foreign governments and foreign-controlled entities. Democrats have argued that Trump has violated the U.S. Constitution through his hotel businesses with foreign governments.

"I intend to continue this investigation in the next Congress," he wrote.

Cummings has said he plans to conduct oversight of the Trump administration while attempting to work with the White House on kitchen-table issues, including postal reform and lowering prescription drug prices.