Story highlights Michael Flynn was formerly President Donald Trump's national security adviser

A committee revealed earlier this year Flynn never documented money he received from RT-TV

(CNN) A pair of top House Democrats are digging into whether former national security adviser Michael Flynn may have misled officials on his security clearance form about two Middle East trips -- including one reportedly about building $100 billion worth of nuclear energy plants with help from Russia's nuclear power agency.

The top Democrats on the House oversight committee and the House foreign affairs committee sent a request to Flynn's lawyers -- as well as two consultants -- seeking additional documents about a summer 2015 trip he took to the Middle East to float a nuclear energy deal involving Russia.

The letter cites a recent Newsweek article detailing Flynn's previously undisclosed trip and a plan that involved Saudi Arabia selling energy from the nuclear projects to US allies in the Middle East and a promise from those Gulf countries to purchase $100 billion in arms from Russia that otherwise would have been sold to Iran.

Rep. Elijah Cummings, the top Democrat on the oversight committee, and Rep. Eliot Engel, the top Democrat on the foreign affairs committee, also asked for more details about an October 2015 trip Flynn took to the Middle East, citing details from Flynn's security clearance, including what Flynn told investigators. The hotel Flynn says he stayed at does not exist, and there is no record of a travel companion he took with him, Cummings and Engel wrote.

The request comes just two months after the House oversight committee revealed that Flynn never documented payments he received from RT-TV, generally considered to be an arm of the Russian government, on his 2016 application for a renewed security clearance. Then-House oversight Chairman Jason Chaffetz noted at the time that Flynn may have broken the law, but also said that was not a determination for congressional investigators to make.

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