The Senate Intelligence Committee has requested documents and testimony from the son of President Trump's former national security adviser, Michael G. Flynn, but has not heard back from the 34-year-old or his lawyer, according to a report Tuesday.

The committee could subpoena Flynn and force him to cooperate as they investigate possible collusion between Trump associates and Russia during the 2016 election.

Flynn is a person of interest in the committee's probe, due in part to his work as an aide and travel buddy for his father's Flynn Intel Group, NBC reported.

In addition, both Flynns traveled to Moscow in 2015 to attend a dinner for state-funded media outlet RT. A picture from the event shows the senior Flynn sat next to Russian President Vladimir Putin at the dinner.

If subpoenaed, Michael G. Flynn could plead the Fifth Amendment in order to avoid testimony against himself or his father.

The son is also being investigated by Special Counsel Robert Mueller's federal team of attorneys.

On Sept. 14, Flynn tweeted, "I'm not the sub of any federal investigation."