WASHINGTON — Revelations earlier this year that former National Security Adviser Michael Flynn was not telling the truth about his conversations with a Russian ambassador were concerning, Republican Senator Roy Blunt, a member of the Senate’s Select Committee on Intelligence, acknowledged Sunday.

"What was particularly wrong was General Flynn not being truthful about the substance of what he said and the campaign was apparently, or the transition rather, was apparently concerned about that early on, and it appears they should have been," Blunt said in an interview on NBC's "Meet The Press" when asked about indications that the Trump transition itself was warned about Flynn’s connections to Russia and conversations he had with the ambassador.

This Monday, Sally Yates, a former deputy attorney general under President Obama who was then pushed out by Trump early on, will testify in front of a Senate Judiciary subcommittee about Russia’s attempts to interfere with the last election, and she is expected to speak about what she knew of conversations between Flynn and Russian Ambassador Sergey Kislyak.

Yates was fired in January, ostensibly for refusing to defend the administration's travel ban in court.

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That Senate subcommittee is one of a number of investigations within Congress looking into Russian attempts to interfere in the 2016 elections, in addition to inquiries in the Senate and House Intelligence Committees.

Meanwhile, Sen. Dianne Feinstein, D-Calif., a member of the Senate’s Select Committee on Intelligence, said on "Meet The Press" that Yates "apparently has some information as to who knew what when that she is willing to share. And that would be what she knew about Michael Flynn’s connections to Russia and exactly what she knew they were."

"I don’t want to, in any way, say that I know what she’s going to say because I don’t," Feinstein continued. "But there are so many questions here as to who knew what when, what was done with this."

Sen. Blunt said on “Meet The Press” that it’s undisputable that Russia attempted to interfere with the 2016 election, and warned that the United States must prepare to guard itself from such interference in upcoming votes.

“There’s no question there was Russian interference in our elections just like we’re seeing now in France and seen in Germany. In fact in Europe we’ve seen for well over a decade the Russians trying to interfere. So we need to look at that, that’s one issue, we need to look at that in a way that better prepares us for 2018 and 2020."

He didn’t know why Trump has been hesitant make similarly firm statements about whether or not Russia was involved.

“I don't know what the president's view of this would be, because I haven't talked to him about it,” Blunt said.

He believed the president’s concerns about a “witch hunt” were based on a number of concurrent investigations over whether or not there was any collusion with associates of the Trump campaign.

“We’re going to determine whether there was any or not, and where those facts lead us. I'm not sure that there's any reason for the president to believe that there was collusion between his campaign. I think the president has to understand at this point that the Russians were doing things to both increase their influence.”

Blunt also defended the work of his committee as they continue to investigate the matter.

“I think the Senate Intelligence Committee is the one committee that’s been asked to reach conclusions here, and that conclusion needs to include talking to anybody that a reasonable person thinks we should’ve talked to, looking at anything that a reasonable person would think we should’ve looked at, and hopefully a largely bipartisan consensus of ‘here’s what we found’ — and I think what you saw this week was the indication that that process of now bringing individuals in after a tremendous background effort to see what we ought to be asking is happening," said Blunt.