The son of former national security adviser Michael Flynn reportedly hasn't responded to requests from the Senate Intelligence Committee for documents and testimony in the Russia investigation.

Michael Flynn Jr. served as his father's aide, helping with day-to-day operations and regularly accompanying his father on business travels for his consulting company, Flynn Intel Group, three sources familiar with the matter told NBC News in a report on Tuesday.

The elder Flynn has come under scrutiny for financial and personal connections to Moscow.

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The panel is interested in hearing about Flynn Jr.'s involvement with his father as he attended key meetings, including a celebration dinner where the elder Flynn sat next to Russian President Vladimir Putin during his now-infamous trip to Russia in 2015.

The panel's leadership declined the NBC News request for comment on the request, as did Flynn Jr.’s lawyer, Barry Coburn.

If Flynn Jr. denies the committee's request, the panel could add additional pressure to get the younger Flynn to comply by issuing a subpoena.

Justice Department special counsel Robert Mueller also reportedly is set on talking to Flynn Jr. about his involvement with his father's business and travels.

Flynn Jr. has denied that he's a target in the investigation, tweeting in mid-September, “I’m not the [subject] of any federal investigation.”

Michael Flynn was ousted from his top White House role earlier this year after reports surfaced that he had misled Vice President Pence about his conversations with Russia's former ambassador to the U.S. about American sanctions on the Moscow.

Sen. Richard Burr Richard Mauze BurrRep. Mark Walker says he's been contacted about Liberty University vacancy Overnight Defense: Trump rejects major cut to military health care | Senate report says Trump campaign's Russia contacts posed 'grave' threat Senate report describes closer ties between 2016 Trump campaign, Russia MORE (R-N.C.), the chairman of the Senate Intelligence Committee, and Sen. Mark Warner Mark Robert WarnerIntelligence chief says Congress will get some in-person election security briefings Overnight Defense: Trump hosts Israel, UAE, Bahrain for historic signing l Air Force reveals it secretly built and flew new fighter jet l Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' House approves bill to secure internet-connected federal devices against cyber threats MORE (Va.), the top Democrat on the panel, said in a press conference earlier this month that the committee is expanding the scope of its investigation into Russian meddling.

The Justice Department and several congressional panels are leading investigations into whether President Trump's campaign aides colluded with the Russians and the extent of Russian interference in the 2016 presidential election.