Maine’s senior senator is calling for Donald Trump Jr. to appear before the Senate Intelligence Committee that’s probing possible collusion between the president’s campaign and Russia during last year’s election.

Susan Collins, R-Maine, told reporters Monday the panel “needs to interview him and others” who attended a meeting in June 2016 in Trump Tower, where a Russian lawyer sought to provide dirt on Democratic presidential contender Hillary Clinton.

[MORE: Trump Jr. says he, Jared Kushner, Paul Manafort met with Russian lawyer last June]

Trump’s eldest son met with a Kremlin-connected attorney, Natalia Veselnitskaya, along with the campaign’s chairman at the time, Paul Manafort, and Trump son-in-law Jared Kushner.

The New York Times reported over the weekend about the previously unknown session.

[MORE: Kremlin denies knowledge of Donald Trump Jr. meeting with Russian lawyer during 2016 campaign]

Trump said in a statement that the woman “had information that individuals connected to Russia were funding the Democratic National Committee and supporting Mrs. Clinton.”

But, he said, her comments proves “vague, ambiguous and made no sense” and it “quickly became clear that she had no meaningful information.”

The Times said Trump agreed to the meeting arranged by a former British tabloid journalist who worked on the Miss Universe pageant, one of the businesses then-operated by the president.

Collins and Sen. Angus King, I-Maine, each serve on the 15-member Senate Intelligence Committee that’s been looking into Russian interference in the election and whether there are any improper ties between President Donald Trump and Russia.

U.S. intelligence agencies have concluded Russia engaged in a widespread effort that included hacking and propaganda in a bid to help Trump defeat Clinton in the presidential race. Whether Trump knew anything about it remains uncertain.