WASHINGTON — The Senate Intelligence Committee has subpoenaed Donald Trump Jr. to answer questions about his contention that he had only limited knowledge of a project to build a Trump Tower in Moscow, a source with direct knowledge told NBC News.

The committee, led by Republicans, is nearing completion of its investigation into Russian election interference — a probe that is expected to result in a series of written reports.

The news was first reported by Axios.

Trump Jr. testified before the Senate Judiciary Committee in September 2017. He said he was only "peripherally aware" of the Moscow development proposal, which was kept secret from voters.

Michael Cohen, then a lawyer for the Trump Organization, who was pursuing the project, told the committee a different story. He testified that he briefed Trump Jr. and his sister Ivanka Trump about the project "approximately 10" times.

Cohen, now serving a three-year prison sentence, pleaded guilty to lying to the committee about the timing of the project when he said it was abandoned in January 2016, before the heart of the Republican primary campaign.

In fact, it continued until June 2016, even as Trump was telling the public he had no business dealings with Russians.

In an interview with Fox News' Laura Ingraham in January 2019, Trump Jr. downplayed his family's role in the project, saying, "the reality is this wasn't a deal — we don't know the developer. We don't know the site. We don't know anything about it. Ultimately, it was Michael Cohen essentially trying to get a deal done."

According to special counsel Robert Mueller's report, Trump authorized and remained interested in the Moscow project, which was described as "highly lucrative."

The source with direct knowledge said the Senate Intelligence Committee also wants to ask Trump Jr. about his account of what he told his father and other colleagues about the June 2016 meeting with Russians in New York's Trump Tower.

Trump Jr. told the Senate Judiciary Committee that he didn't tell his brother-in-law Jared Kushner or Trump campaign chair Paul Manafort what the meeting was about, or inform his father about the meeting at all.

The Mueller report appears to contradict Trump Jr.'s assertion. Cohen told investigators that Trump Jr. told his father that the meeting with Russians was going forward.

Trump Jr. was not charged by Mueller over his Senate testimony, after months of speculation that such charges were possible.

This marks the first known congressional subpoena of a member of the president's immediate family.

A source close to Trump Jr. said that Trump Jr. had "already been cleared by Mueller after a two-year investigation" and testified for 27 hours in front of various congressional committees. "Don continues to cooperate and by producing documents and is willing to answer written questions," said the source, "but no lawyer would ever agree to let their client to participate in what is an obvious PR stunt."