Former White House national security adviser Michael Flynn was paid more than $67,000 by Russian companies before the U.S. presidential election, according to documents released on March 16 by a Democratic congressman.

U.S. Representative Elijah Cummings of Maryland asked President Donald Trump's administration to provide a comprehensive record of Flynn's contacts with foreign governments and interests.

The documents show that Flynn accepted $33,750 from Russian state-backed television channel RT for appearing at a Moscow event in December 2015, a few months before he began formally advising Trump's campaign.

Flynn's financial relationship with RT may violate a constitutional provision against gifts from foreign governments, Cummings said.

He released documents obtained during an inquiry conducted by the Committee on Oversight and Government Reform in the U.S. House of Representatives into Flynn's activities before Trump appointed him to become national security adviser.

Trump forced Flynn out as national security adviser last month, after it was revealed that the former Army lieutenant general misled Vice President Mike Pence and other White House officials about his conversations in December with the Russian ambassador to the United States.

Flynn's ties to Russia have been scrutinized by the FBI and are part of House and Senate committee investigations into contacts between Trump campaign officials and Russians.

The newly released files show that RT -- designated by the U.S. intelligence community as a propaganda arm for Russia's government -- also paid for luxury hotel stays and other expenses incurred by Flynn and his adult son, Michael Flynn Jr., during the Moscow trip.

Flynn sat next to Russian President Vladimir Putin during the climax of the televised RT gala.

Cummings said Flynn's acceptance of payments from RT violated the emoluments provision of the U.S. Constitution, which prohibits retired military officers from accepting gifts from foreign powers.

RT identifies itself as an independent news network, but a report by U.S. intelligence agencies made public in January said RT has long been considered by the U.S. government to be a Russian propaganda arm.

In an addition to the RT payments, Flynn was also paid $11,250 for two speeches in Washington -- one in August for Volga-Dnepr Airlines, a Russian charter cargo airline, and a second in September for Kaspersky Government Security Solutions Inc., a U.S. subsidiary of Kaspersky Lab, a Russia-based cybersecurity firm.

With reporting by AP and AFP

