Sen. Lindsey Graham Lindsey Olin GrahamMomentum growing among Republicans for Supreme Court vote before Election Day Video of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral Warning signs flash for Lindsey Graham in South Carolina MORE (R-S.C.) on Tuesday expressed concern after new details emerged regarding Donald Trump Donald John TrumpUS reimposes UN sanctions on Iran amid increasing tensions Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally MORE Jr.'s meeting last year with a Russian lawyer.

"Anytime you're in a campaign and you get an offer from a foreign government to help your campaign, the answer is no," Graham told reporters.

"So I don't know what Mr. Trump Jr.'s version of the facts are. Definitely — he has to testify. That email is disturbing."

Trump Jr. on Tuesday released a chain of emails highlighting his conversations about setting up the meeting with a Russian lawyer offering compromising information on Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonJeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Momentum growing among Republicans for Supreme Court vote before Election Day Warning signs flash for Lindsey Graham in South Carolina MORE.

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The release came after The New York Times reported Trump Jr. was told before the meeting that the harmful information on Clinton was part of a Russian government effort to help his father’s presidential campaign.

Graham said Tuesday he also finds it "odd" that the woman Trump Jr. and other campaign aides met with "knew absolutely nothing."

"I don't know why they would pick somebody for him to meet with that didn't have any information about the Clinton campaign," he said.

"But on it's face, this is very problematic. We cannot allow foreign governments to reach out to anybody's campaign and say we'd like to help you. That is a nonstarter."

Graham acknowledged he knows Trump Jr. and the president's son-in-law Jared Kushner, who also attended the meeting last year, are new to politics.

"But this is going to require a lot of questions to be asked and answered," Graham said.

The Trump White House has maintained there was "no collusion" between the campaign and Russians who the intelligence community said hacked Democratic groups to help Trump win the election.

In the chain, Trump Jr. was offered “some official documents and information that would incriminate Hillary and her dealings with Russia would be very useful to your father.”

The president’s oldest son responded at one point, “If it’s what you say I love it.”