The top Democrats on the House Oversight Committee and Committee for Foreign Affairs on Monday said former National Security Adviser Michael Flynn failed to report a trip he took to Saudi Arabia to “pursue a joint U.S.-Russian business venture.”

According to a Newsweek report published earlier in June, Flynn traveled abroad in June 2015 to work on a “joint U.S.-Russian (and Saudi-financed) program to get control over the Arab world’s rush to acquire nuclear power.”

Reps. Elijah Cummings (D-MD) and Eliot Engel (D-NY), respectively ranking members of those committees, cited the Newsweek report in a letter requesting documents and communications from Flynn’s company and two other businesses reportedly involved in the deal.

They also cited Flynn’s testimony in June 2015 before the House Foreign Affairs Committee that he had recently returned from a “fairly extensive trip to the Middle East” and was concerned about “developing nuclear capabilities” there.

“We have no record of General Flynn reporting this trip or any contacts with foreign officials on his security clearance renewal application or in his interview with security clearance investigators,” Cummings and Engel wrote.

They noted that “soon after” Flynn reportedly made the trip, Saudi Arabia announced a deal with Rosatom, Russia’s state nuclear power plant builder, “that resulted in a $100 billion deal in 2016 to build 16 nuclear power units.”