WASHINGTON (Reuters) - Former White House national security adviser Michael Flynn likely broke the law by failing to get permission to be paid for a trip to Russia in 2015, the leaders of a House of Representatives committee said on Tuesday.

During the visit, Flynn, a retired lieutenant general who advised Donald Trump’s presidential campaign, dined with Russian President Vladimir Putin.

“General Flynn had a duty and an obligation to seek and obtain permission to receive money from foreign governments,” Jason Chaffetz, the Republican chairman of the House Oversight Committee, told reporters. “It does not appear to us that that was ever sought, nor did he ever get that permission.”

The oversight panel is looking into whether Flynn fully disclosed payments from Russian, Turkish or other foreign sources.

“As a former military officer, you simply cannot take money from Russia, Turkey or anybody else. And it appears as if he did take that money. It was inappropriate and there are repercussions for the violation of law,” Chaffetz said.

Flynn was forced to resign on Feb. 13 for failing to disclose talks with Sergei Kislyak, the Russian ambassador to the United States, about U.S. sanctions on Moscow and misleading Vice President Mike Pence about the conversations, which occurred in December before Trump took office.

He is a subject in investigations by intelligence committees in the House and Senate, as well as the Federal Bureau of Investigation, into allegations Russia meddled in the 2016 U.S. election. Russia has denied the allegations, which have cast a shadow over the first 100 days of Trump’s presidency.

Representative Elijah Cummings, the top Democrat on the oversight panel, said it also appeared as if Flynn had not fully disclosed the payments after the fact as required, saying a failure to do so would be a felony.

An attorney for Flynn did not respond to a request for comment from Reuters, but he told ABC News the retired general had briefed the Defense Intelligence Agency, which is part of the Defense Department, before and after the Russia trip.

“He answered any questions that were posed by DIA concerning the trip during those briefings,” attorney Robert Kelner said, according to a statement ABC News posted on Twitter.

Asked about the assertions that Flynn appeared to have violated the law, White House spokesman Sean Spicer told reporters: “That would be a question for him and law enforcement agencies.”