Michael Flynn in Washington before the inauguration in January. (Chris Kleponis/AFP/Getty Images)

Retired Lt. Gen Michael Flynn, the former national security adviser under President Trump, refused to comply with a Senate Intelligence Committee subpoena as a top House Democrat disclosed portions of new documents suggesting Flynn lied about his Russia ties to federal investigators.

Members of the Senate Intelligence Committee must now meet to vote and decide whether to hold Flynn in contempt or accept his attempt to invoke his Fifth Amendment right against self-incrimination.

The committee has demanded that Flynn provide it with a list of any contacts he had with Russian officials between June 16, 2015, and Jan. 20, 2017.

In a statement late Monday, the committee chairman and vice chairman, Sens. Richard Burr (R-N.C.) and Mark R. Warner (D-Va.), said they were “disappointed” by Flynn’s decision and would “vigorously pursue General Flynn’s testimony and his production of any and all pertinent materials pursuant to the Committee’s authorities.”

Flynn’s refusal comes as Rep. Elijah E. Cummings (D-Md.), the top Democrat on the House Oversight Committee, cited a previously undisclosed document alleging that Flynn had “lied” to security-clearance investigators about payments he received “directly” from Russia for appearing at a December 2015 gala hosted by Russian state-owned media company RT.

(Gillian Brockell/The Washington Post)

In the letter, Cummings cites the March 14, 2016, Report of Investigation indicating Flynn “told security clearance investigators that he was paid by ‘U.S. companies’ when he traveled to Moscow” for that gala and told investigators that “he has not received any benefit from a foreign country.” But payment vouchers and other documents showed that Russia had “directly” paid for Flynn’s airfare, accommodations and other expenses, Cummings wrote, citing the investigators’ report.

Cummings stressed his view that the Oversight Committee’s chairman, Rep. Jason Chaffetz (R-Utah), must issue subpoenas against various White House officials to learn what “top officials knew about General Flynn — and when they knew it.”

But thus far, the only witness who has been subpoenaed as part of the congressional probes into Russian meddling during the 2016 elections is not complying with the request.

In a letter to Burr and Warner on Monday, Flynn’s attorneys cited the Justice Department’s recent appointment of Robert S. Mueller III as special counsel for the federal investigation into Russian interference in the election as reason to steer clear of congressional probes. They argued that Mueller’s appointment creates new dangers for Flynn and gives “rise to a constitutional right not to testify.”

Across Congress, lawmakers have openly worried that Mueller’s probe might serve to muzzle witnesses they had hoped would participate in the various committees’ parallel probes. At this point, former FBI director James B. Comey is one of the few central figures in the investigation who has committed to testify publicly, pledging to appear before the Senate Intelligence Committee at some point after Memorial Day.

But even he is going to check with Mueller first, according to a tweet from Chaffetz, who spoke with Comey by phone Monday.

In their letter, Flynn’s attorneys stressed that Flynn had offered “to give a full account” to Intelligence Committee investigators, but only in exchange for “assurances against unfair prosecution” — in other words, immunity. No committee has offered Flynn immunity in exchange for his testimony.

Still, the Senate panel has some recourse. Members will have to meet to review Flynn’s refusal to cooperate with the subpoena and can vote not to accept it. At that juncture, the committee could vote to recommend holding Flynn in contempt, though the full Senate would have to vote in favor of contempt before court proceedings would be triggered.

At this point, opinions among committee members about what to do are mixed.

“You would think they’d want to clear things up. You would think that someone would want to give us the facts, unless you’re hiding something,” Sen. Joe Manchin III (D-W.Va.), a panel member, said Monday, adding that the committee would probably “discuss actions we can take” this week.

Another panel member, Sen. Susan Collins (R-Maine), said that if Flynn “had just refused to turn over documents without invoking his constitutional rights, then my approach would be to explore a contempt-of-Congress citation.” But, she added, “I’m very respectful of their privilege not to incriminate themselves, and so I think we have to proceed carefully.”

While the Fifth Amendment is commonly applied to giving testimony, Flynn’s attorneys argued that by creating or handing over the documents the committee had requested, their client would essentially be giving testimony about the existence of those conversations and, thus, potentially incriminating himself.

“Producing documents that fall within the subpoena’s broad scope would be a testimonial act, insofar as it would confirm or deny the existence of such documents,” they wrote.

Flynn was forced to resign as national security adviser in February after it emerged that he had not been fully forthcoming with Vice President Pence about conversations he had with Sergey Kislyak, the Russian ambassador to the United States, before Trump’s inauguration.

In addition to those conversations and the RT payments, Flynn has come under scrutiny for collecting more than $500,000 for lobbying work on behalf of Turkish interests.

Matea Gold, Karen Tumulty, Tom Hamburger and Ed O’Keefe contributed to this report.