Virginia Sen. Mark Warner said in an interview on CNN's "State of the Union" that he wanted to question everyone involved in the meeting as part of the committee's investigation into Russian interference in the 2016 election.
"Whether we'll be able to get the Russian nationals to come over and testify is an open question," Warner said. "Those people that our committee has jurisdiction over, the Americans, I sure as heck want to talk to them."
But Warner said he wanted to get documents from them first so that the committee members have as much information as possible before questioning them.
"Clearly if we don't have all the information," Warner said. "What we'll see, and what I'm afraid of, is these individuals don't seem to disclose everything, or don't tell the whole truth, until they have evidence put in front of them."
Maine Sen. Susan Collins, a Republican on the committee, said in an interview later on the program that she too wanted the committee to ask for all documents related to any contact between the campaign and "the Russian government or its emissaries."
The June meeting involved
Donald Trump Jr., son-in-law Jared Kushner, then-campaign manager Paul Manafort, Russian lawyer Natalia Veselnitskaya, publicist Rob Goldstone, Russian-American lobbyist Rinat Akhmetshin and at least two other people, sources famliar with the meeting told CNN. The meeting has drawn widespread scrutiny since The New York Times reported on it last weekend. In the wake of the Times' reporting, Trump Jr. posted a series of emails on Twitter between himself and Goldstone, an acquaintance who pointed to the Russia attorney as the source of potentially damaging information on Hillary Clinton as "part of Russia and its government's support for Mr. Trump."
Trump Jr. accepted Goldstone's offer to meet with the Russian lawyer and went on to set up the meeting at Trump Tower. The President has maintained having no knowledge of the meeting until the Times' reporting.
Jay Sekulow, a member of the President's legal team, reiterated on "State of the Union" that Trump was unaware of the meeting.
"The President was not engaged in this, was not aware of it," Sekulow said.
Warner, however, questioned that assertion.
"Frankly, it's a little bit unbelievable that neither the son or the son-in-law ever shared that information with their dad, the candidate," Warner said.
Warner said several times that there was reason to doubt the credibility of senior members of the Trump administration -- of which Trump Jr. is not a member -- and accused Trump Jr. of lying about the meeting.
"We don't know because we don't know really what happened at the meeting," Warner said. "What we do know is Donald Trump Jr. did not tell the truth a variety of times."
Trump Jr., in a statement, initially described
the meeting as primarily about adoption policy before conceding in a subsequent statement that he had agreed to the meeting in the hope he might get damaging information on Clinton.
Following his release on Twitter of the email exchange between himself and Goldstone, Trump Jr. did an interview
with Fox News' Sean Hannity, a staunch supporter of the President. Trump Jr. said he would be willing to go under oath to speak about the meeting.
Sekulow pointed to Trump Jr.'s comments in the interview that he had now disclosed everything about the meeting.
"I think it speaks for itself," Sekulow said.
Sekulow also maintained the meeting was legal and said people should not criticize the Trump campaign members for attending the meeting given the breakneck speed of the presidential campaign.
"I don't think that's fair to Donald Trump Jr., to Jared Kushner or to Manafort for that matter," Sekulow said.