Former White House national security adviser Michael Flynn (Carlos Barria/Reuters)

House Democratic leaders are pressing former national security adviser Michael Flynn for documents and details related to two trips he made to the Middle East in 2015 that they argue he failed to disclose — in part or in whole — on security clearance forms.

According to the ranking Democrats on the House Oversight and House Foreign Affairs committees — Elijah E. Cummings (Md.) and Eliot L. Engel (N.Y.), respectively — Flynn’s security forms and interviews revealed a previously unreported, six-day trip he made to Saudi Arabia in October 2015, in which he claimed to have stayed at a hotel that does not appear to exist, have traveled with a friend who was never named, and have spoken at a conference that none of his handling bureaus were aware of.

According to congressional testimony Flynn gave in June 2015, Flynn also made an earlier trip that involved talks about developing nuclear power in the region. But Flynn never documented the trip on his security clearance forms at all, according to Cummings and Engel.

Cummings and Engel sent their letter requesting documents on Monday to Flynn’s lawyers and the heads of consulting companies X-Co Dynamics Inc./IronBridge Group and ACU Strategic Partners.

Flynn is under scrutiny by several investigations into Russian meddling in the 2016 president election and any possible collusion between President Trump’s campaign and that effort.

Newsweek recently reported that Flynn had traveled to the Middle East to promote a potential U.S.-Russian venture involving those companies to develop nuclear power facilities. But Flynn’s financial disclosure forms indicate that his business affiliation with X-Co/IronBridge began only in August 2015 — two months after his initial trip — according to Cummings’s and Engel’s letter.

Shortly after Flynn’s summer trip, Cummings and Engel pointed out, Saudi Arabia announced an agreement with Rosatom, Russia’s state nuclear energy company, that would prove to be worth about $100 billion.

“If this press report is accurate, General Flynn’s failure to report this trip and any contacts with foreign government officials about this Saudi-Russian nuclear proposal appears to be a potential violation” of the law, Cummings and Engel wrote, stressing that they have “no record of General Flynn identifying on this security clearance renewal application . . . even a single foreign government official he had contact with in the seven years prior” to submitting the form.

Their letter requests “all documents and communications referring or relating to any relationship” between X-Co Dynamics Inc./IronBridge Group or ACU Strategic Partners and either Flynn or his business, the Flynn Intel Group. They also request information about “all bids, pitches, contracts, agreements, invoices, and billings,” anything related to Flynn’s travel or billings, as well as any internal documents from the companies referring to Flynn or the Flynn Intel Group.

Flynn’s attorney declined to comment on the House Democrats’ letter.

Cummings’s and Engel’s letter does not impose a deadline, nor does it have the signatures of their committees’ chairmen, Reps. Trey Gowdy (R-S.C.) and Edward R. Royce (R-Calif.)