REVEALED: Mike Flynn accepted payments from Russian companies while he had top-secret security clearance
Lieutenant General Michael Flynn (ret.), National Security Advisor Designate speaks during a conference on the transition of the US Presidency from Barack Obama to Donald Trump at the US Institute Of Peace in Washington DC, January 10, 2017 (AFP Photo/CHRIS KLEPONIS)

New documents reveal Michael Flynn was paid tens of thousands of dollars by Russian companies -- which he later denied -- shortly before he joined Donald Trump's campaign as an adviser.

The documents obtained by a congressional oversight committee show Flynn accepted payment, which he had claimed through his speakers bureau, from the state-owned RT network for an all-expenses-paid, three-day trip to Moscow in December 2015, reported Yahoo News.

RT paid $45,386 for Flynn and his son, Michael Flynn Jr., to fly to Moscow to speak at the English-language network's 10th anniversary celebration, where he dined at the same table as Russian President Vladimir Putin and Green Party presidential candidate Jill Stein.

Flynn's speaking agency, Leading Authorities, took a 25 percent commission for the payment, which left $33,750 for the retired U.S. Army general.

Other documents obtained by the congressional committee show Flynn was paid $11,250 each by a Russian air cargo company and a Russian cybersecurity company, reported the Wall Street Journal.

The cargo company had been suspended as a United Nations vendor following corruption scandal, and the cybersecurity company was trying to expand its business with the U.S. government.

Those engagements took place in summer and fall of 2015, as he continued to maintain a top-secret security clearance after his firing the year before as director of the Defense Intelligence Agency.

Flynn was fired last month as Trump's national security adviser after misleading Vice President Mike Pence about his communications with the Russian ambassador during the presidential transition.

After his firing, Flynn's lobbying firm filed documents disclosing the disgraced national security adviser had worked during the presidential campaign on behalf of a shadowy man with close ties to the Turkish government.

Flynn, who was receiving classified briefings as part of the campaign, published a controversial op-ed shortly after Trump's election calling for better U.S.-Turkey relations.