Mike Flynn was paid to work for Russia's top cybersecurity firm while he still had top-secret security clearance

Former National Security Adviser Michael Flynn was paid by several Russian companies before becoming an adviser to Donald Trump, according to new documents obtained and published by the House Oversight Committee on Wednesday, including $11,250 by Russia's top cybersecurity firm, Kaspersky, in 2015. Flynn was also paid $11,250 by the Russian charter cargo airline Volga-Dnepr Airlines, according to the documents.

Flynn was paid for his work with both companies while he still had top-secret level security clearance, a year after he was fired as head of the Defense Intelligence Agency, the Wall Street Journal's Shane Harris reported.

Screenshot/House Oversight Committee

Flynn was forced to resign as national security adviser in early February for misleading Vice President Mike Pence about his phone calls with the Russian ambassador to the US, Sergey Kislyak. He was also paid $33,750 to speak at gala celebrating the 10th anniversary of Russia's state-sponsored news agency, RT, in December 2015, the documents showed.

The Oversight Committee received the documents earlier this month, after top Democratic lawmakers called on the Defense Department to investigate whether Flynn ran afoul of the US Constitution by being paid to speak at the RT gala.

Flynn told The Washington Post that he had been paid to speak at the gala, but had not previously disclosed his work for either Kaspersky or Volga-Dnepr Airlines.

"I cannot recall any time in our nation's history when the President selected as his National Security Advisor someone who violated the Constitution by accepting tens of thousands of dollars from an agent of a global adversary that attacked our democracy," Rep. Elijah E. Cummings, the ranking Democratic member of the committee, wrote in a letter to Trump on Thursday.

He added: "I also cannot recall a time when the President and his top advisers seemed so disinterested in the truth about that individual's work on behalf of foreign nations-whether due to willful ignorance or knowing indifference."