WASHINGTON >> Two top House Democrats are questioning whether Michael Flynn failed to report a 2015 trip to the Middle East to federal security clearance investigators, a potential omission that could add to the legal jeopardy President Donald Trump’s former national security adviser faces over the truthfulness of his statements to authorities and on government documents.

The lawmakers — Rep. Elijah Cummings, D-Md., and Rep. Eliot Engel, D-N.Y. — said in a letter released today that they believe Flynn may have violated federal law by failing to disclose the trip, which they believe involved a proposal to provide nuclear power to several Middle Eastern countries, and any foreign contacts he had during another trip to the region that year.

The letter from Cummings, the ranking Democrat on the House oversight committee, and Engel, the ranking Democrat on the House foreign affairs committee, is the latest to call attention to potential problems with what Flynn reported to the U.S. government about his foreign travel, contacts and business after he left the Defense Intelligence Agency in August 2014.

Federal and congressional probes have been looking closely at Flynn’s foreign travel and contacts as part of investigations into Russia’s meddling in the 2016 presidential election and any possible collusion with associates of Trump or his campaign.

Separately, federal investigators have been scrutinizing Flynn’s work for a Turkish businessman and the Defense Department’s inspector general has been looking into whether Flynn failed to get U.S. government permission to receive foreign payments. Among those payments was more than $33,000 he received from RT, the Russian state-sponsored television network that U.S. intelligence officials have branded as a propaganda arm of the Kremlin.

Flynn’s attorney, Robert Kelner, declined to comment on the allegations in the letter.

In their letter, Cummings and Engel said they believe Flynn was not forthcoming about a trip to the Middle East in the summer of 2015.

They cited a recent Newsweek report that Flynn flew to Israel and Egypt that summer as part of an effort promoting a U.S.-Russian partnership to construct nuclear reactors for civilian power needs. They also point to Flynn’s June 10, 2015, testimony before a House Foreign Affairs subcommittee.

During the testimony, Flynn told lawmakers he “just came from a trip — fairly extensive trip to the Middle East,” during which the issue of developing nuclear energy in the region came up. But Cummings and Engel said it “does not appear that General Flynn disclosed this trip or any foreign contacts as part of his security clearance renewal process,” noting that intentionally concealing such information from a security clearance form is a felony.

Cummings and Engel also raised questions about an October 2015 trip to Saudi Arabia, which Flynn did report as part of his security clearance review. The review took place in the early months of 2016.

The lawmakers said Flynn told security clearance investigators that he traveled to Saudi Arabia because “as a business owner, he is working on developing business with another country.”

Flynn reported that he went on the six-day trip with a friend, who was also American, to speak at a conference, stayed at a hotel called the King Khaled International Hotel and had the trip paid for by a “work sponsor.”

But congressional staffers could not confirm the existence of such a hotel, though they note the airport in Riyadh shares that name. They also could not find any evidence of a conference that Flynn would have attended during the time frame, noting that three speakers’ bureaus affiliated with Flynn did not report being involved with the trip or a conference in Saudi Arabia.

In the letter, the lawmakers asked Flynn’s former firm, Flynn Intel Group, to provide additional information about his foreign travel and his involvement with two other companies who spearheaded the nuclear power plan.

In financial disclosures Flynn filed out earlier this year, he reported serving as an adviser between August 2015 and last December to one of the companies, identified as X-Co Dynamics/Iron Bridge Group.

X-Co Dynamics is a Virginia-based consulting firm headed by former U.S. Rear Admiral Michael Hewitt, whose board of retired military advisers included former National Security Agency chief Keith Alexander and former Marine Corps General James “Hoss” Cartwright, who was prosecuted last year for lying to the FBI in a leak investigation.

A representative for Hewitt reached by the AP on Monday afternoon said he was not available because he was traveling.

Flynn did not detail his work with X-Co Dynamics in the disclosure, but the Newsweek report alleged that Flynn’s trip to Israel and Egypt in summer 2015 was part of a private effort by the firm to advance the idea of a massive ring of atomic reactors that would be built by the U.S. nuclear industry and the Russian government and largely bankrolled by Saudi Arabia.

According to an internal memo obtained by Newsweek, the project was the brainchild of ACU Strategic Partners, a U.S. firm promoting the idea of a partnership between the U.S., Saudi Arabia, Egypt, Jordan, Kuwait and the United Arab Emirates to build and operate 40 nuclear power reactors across the Middle East. Russia would have financial incentive to join the project, according to the ACU plan, because it would take the lead in building the plants and providing a burial ground for their waste.

ACU Strategic Partners managing director Alex Copson did not immediately respond to an email from the AP seeking comment.

Newsweek reported that Flynn’s role in the project, via X-Co Dynamics, was to design and put into play “a vast security network for the entire enterprise.” Flynn’s financial disclosure did not show any financial payment from X-Co Dynamics for his involvement.

Newsweek reported that the proposed deal was scuttled by the Obama administration. Saudi Arabia later signed a deal with Russia’s nuclear agency, Rosatom, to build 16 reactors.