The House Oversight Committee's top-ranking Republican and Democrat said in a joint press conference on Tuesday that former National Security Adviser Michael Flynn appeared to have broken the law by not disclosing payments he received from Russia in his 2016 security clearance application.

Republican Rep. Jason Chaffetz, the committee's chairman, and Rep. Elijah Cummings, the ranking Democrat, told reporters they had obtained the SF86 security clearance application that Flynn filed in January 2016, one month after he traveled to Moscow to speak at a gala celebrating the 10th anniversary of Russia's state-owned news agency, Russia Today.

Documents the committee obtained later from Flynn's speaking bureau revealed that Flynn was paid about $33,000 for the speaking engagement. But Chaffetz and Cummings said he appeared not to have disclosed those funds on his application.

Chaffetz also said Flynn, a former military officer who headed the Defense Intelligence Agency from 2012 to 2014, did not appear to have obtained permission from his superiors before traveling to Moscow.

"I see no evidence or no data to support the notion that Gen. Flynn complied with the law," Chaffetz said. "He was supposed to seek permission and receive permission from both the secretary of state and the secretary of the Army prior to traveling to Russia to not only accept that payment, but to engage in that activity."

Chaffetz said the response the committee was getting from the Pentagon was that "there is no information on Flynn's trips or payments [on his SF86 form] and that, we believe, is the potential violation."

"No former military officer is allowed to accept payments from a foreign government, and my guess is this is probably not the first time this has happened," he added.

Flynn's lawyer, Robert Kelner, reiterated in a statement on Tuesday that Flynn disclosed his trip to Moscow with the Defense Intelligence Agency before he traveled there.

"As has previously been reported, General Flynn briefed the Defense Intelligence Agency, a component agency of the DoD, extensively regarding the RT speaking event trip both before and after the trip, and he answered any questions that were posed by the DIA concerning the trip during those briefings."

Chaffetz and Cummings held the press conference after being briefed on classified documents the Oversight Committee had requested from the Defense Department related to Flynn's lobbying work and whether he had properly disclosed payments he received from foreign entities.

Cummings said the committee had asked the White House, in which Flynn served as President Donald Trump's national security adviser for less than a month, for more information about his financial disclosures.

But the Trump administration has so far "refused to provide the committee with a single piece of paper in response to our bipartisan request," Cummings said, "and that is unacceptable."

In a letter to the Oversight Committee dated April 19, White House Director of Legislative Affairs Marc Short referred the committee to the Defense Department for the documents related to Flynn's security clearance and "contacts with foreign nationals" that predated his time at the White House.

Short wrote that the White House would be "unable to accommodate" the committee's requests for information about Flynn's contacts with foreign nationals after he was appointed national security adviser. Short said that much of that information was classified.

Flynn was forced to step down from his position in February after only 24 days amid revelations that he misled Vice President Mike Pence about his conversations with Russia's ambassador to the US, Sergey Kislyak. Flynn's contact with Kislyak and other foreign nationals is being investigated by the House Intelligence Committee, which Chaffetz said would take the lead on examining whether those contacts themselves were inappropriate.

Flynn last month offered to testify before the congressional intelligence committees in exchange for immunity from prosecution — a signal to some legal experts that he thought he may have committed a crime.

Cummings said that while Flynn's negligence on his SF86 forms could be punished by up to five years in prison, that decision was not up to the Oversight Committee.

Documents obtained by the committee also revealed that Flynn was paid $11,250 by Russia's top cybersecurity firm, Kaspersky, and another $11,250 by the Russian charter cargo airline Volga-Dnepr Airlines for two speaking engagements in 2015.

Flynn belatedly registered as a foreign agent with the Department of Justice in March for his lobbying work last year on behalf of a Turkish businessman with ties to the Turkish government. Flynn's firm, Flynn Intel Group, was paid about $500,000 by the businessman, Ekim Alptekin, between August and November.