WASHINGTON — House Democrats said Tuesday they would begin a full-scale inquiry into White House involvement in a proposed venture to bring nuclear power facilities to Saudi Arabia, citing whistleblower claims that administration officials disregarded warnings that potential conflicts of interest could put U.S. security at risk.

In a 24-page report from the House Oversight and Reform Committee, the Democrats said their concerns centered on actions taken in the early weeks of the Trump administration to secure government backing for a plan to build a series of nuclear power plants across Saudi Arabia. But they said there was evidence as recently as last week that the White House was still considering the proposal.

Claims presented by whistleblowers and White House documents obtained by the committee show that the company backing the nuclear plan, IP3 International, and allies in the White House were working so closely that the company sent a draft memo to Michael T. Flynn, Trump’s former national security adviser, to circulate just days after the inauguration. Flynn had worked on the plan for IP3 during the Trump campaign and transition, the Democrats said, and continued to advocate for it in the White House.

Even after Flynn left the White House in February 2017, officials on the National Security Council pushed ahead, the Democrats said, ignoring advice from the NSC’s ethics counsel and other lawyers to cease all work on the plan because of potentially illegal conflicts.

The draft memo also referenced another close Trump associate, Thomas J. Barrack, who served as chairman of the president’s inaugural committee. It said that Trump had appointed Barrack as a special representative to implement the plan, which it called “the Middle East Marshall Plan.” The memo also directed agencies to support Barrack’s efforts.

The Democrats’ investigation comes at a sensitive time, when lawmakers of both parties are incensed over the Trump administration’s reluctance to punish Saudi Crown Prince Mohammed bin Salman and the Saudi government over the slaying of Washington Post journalist Jamal Khashoggi. As supporters of the nuclear deal maneuvered in opening days of the Trump White House, the president’s son-in-law, Jared Kushner, was orchestrating what would be Trump’s first overseas trip as president, to Saudi Arabia, and met on his own with the then-deputy crown prince, Salman, before the prince became the power behind the Saudi throne.

At a March 2017 meeting, a National Security Council aide tried to revive the IP3 plan “so that Jared Kushner can present it to the president for approval,” the Democratic report said. Kushner is scheduled to travel to the region next week to brief diplomats on the economic portions of the Trump administration’s Middle East peace plan.

Rep. Elijah E. Cummings, D-Md., chairman of the Oversight Committee, first disclosed claims brought to him by one of the whistleblowers in November 2017, and called on the committee’s Republican chairman at the time to further scrutinize them. The Republicans did not touch it, so Tuesday, after laying out a more detailed timeline of events, Cummings said he was now able to do that work himself.

“Further investigation is needed to determine whether the actions being pursued by the Trump Administration are in the national security interest of the United States or, rather, serve those who stand to gain financially as a result of this potential change in U.S. foreign policy,” Cummings’ staff wrote in the report.

The export of U.S. nuclear technology that could be used to create nuclear weapons is strictly controlled under the Atomic Energy Act of 1954. The act says that Congress must approve such exports, and at least one of the whistleblowers claimed that officials involved ignored warnings about such legal requirements.

A plan like the one advocated by IP3 International has not gone forward to date. But Cummings’ staff said there was evidence that the White House was still kicking around the proposal.

Trump met with nuclear industry executives at the White House last week to discuss expanding their presence internationally, including in the Middle East. Bloomberg reported that the session was organized by Jack Keane, a retired four-star Army general and one of the co-founders of IP3 International.