Updated at 5:41 p.m. ET

Donald Trump Jr. on Tuesday tweeted an email exchange that seemed to show the president's son entertained an offer of Russian government help for his father to be elected president in 2016.

"This is obviously very high level and sensitive information but is part of Russia and its government's support for Mr. Trump," said the text that Trump Jr. posted on Twitter.

In the messages, an intermediary for Russian business allies of the Trumps offer what they call incriminating information about Hillary Clinton. That eventually led to a meeting — set up by music promoter Rob Goldstone — among a Russian attorney, Trump Jr., then-Trump campaign chairman Paul Manafort and President Trump's son-in-law Jared Kushner.

Trump Jr. did not seem bothered by the offer, which brought him and the campaign into a questionable legal area.

"If it's what you say," Trump Jr. replied, "I love it."

It's illegal under federal law to solicit or accept a campaign contribution from a foreign national or foreign government.

On Tuesday, in his first comments about the meeting since it was revealed, President Trump stood by his son.

"My son is a high-quality person and I applaud his transparency," Trump said, in a statement read by White House deputy press secretary Sarah Sanders.

Sanders then referred reporters asking for more details to Trump Jr.'s outside counsel, Alan Futerfas.

Trump Jr. said in his Twitter post on Tuesday that he was posting the messages "to be totally transparent" and that the Russian attorney with whom he met, Natalia Veselnitskaya, ultimately did not provide Trump Jr. with any opposition research about Clinton. The New York Times reports in its story that the paper reached out to Trump Jr. to let him know it had acquired the emails and were planning to publish them, which then led Trump Jr. to post them.

The June 9 meeting at Trump Tower planned in the messages brought together President Trump's business and government contacts in Russia, most of which predate his time in politics.

Goldstone, the music publicist, set up the meeting at the request of Russian pop star Emin Agalarov. Agalarov is the son of Aras Agalarov, a Russian real estate mogul with close ties to Russian President Vladimir Putin.

"Emin just called and asked me to contact you with something very interesting," Goldstone wrote in the initial email. "The crown prosecutor of Russia met with his father Aras this morning and in their meeting offered to provide the Trump campaign with some official documents and information that would incriminate Hillary and her dealings with Russia and would be very useful to your father."

A month after the meeting and this email thread, however, Trump Jr. shrugged away a question from CNN's Jake Tapper about the possibility Russians were trying to help his father's campaign win the election.

"This is, time and time again, lie after lie," he said. "It's disgusting, it's so phony ... I can't think of bigger lies, but that just goes to show you what the DNC and the Clinton camp will do. They will lie and do anything to win."

The email thread between Goldstone and Trump Jr. was also forwarded to Kushner and Manafort.

President Trump has gone back and forth about his own acceptance of Russian interference in last year's presidential election. Sometimes he says he believes it took place but that "others" also may have staged cyberattacks against the U.S., and sometimes he calls it a "witch hunt" invented by Democrats as an excuse for Clinton's loss.

American intelligence agencies, however, are in universal agreement that the Russians interfered.

And the top Democrat on the House Intelligence Committee said the accounts of the setup and the meeting were "very much consistent with Russian practices, their operating procedures."

Rep. Adam Schiff of California told reporters that he suspected this was a way for the Russian government to put its toe in the water to see whether the Trump camp would go along with their offer of help — or report what happened to authorities in the U.S.

"The Russian government had possession of damaging information," Schiff said. "They thought the way to get that back to the Trump campaign to test whether Donald Trump wanted that information was to go through people he had done business with ... They dispatch this advocate for the Kremlin. Why would they choose her? They might choose her because she gives them some deniability, as opposed to someone who has a more direct connection to the government."

Other key members of Congress said they also were bothered by Trump Jr.'s disclosures.

"Anytime you're in a campaign and you get an offer from a foreign government to help your campaign, the answer is no," Sen. Lindsey Graham, R-S.C., told reporters at the Capitol. "That email is disturbing."

Sen. John McCain, R-Ariz., suggested he was not surprised what Trump Jr. had revealed.

"I've said many times in the past, there's another shoe that will drop and there will be other shoes that drop," he said.

And Sen. Tim Kaine, D-Va., said he sees the story inching toward a treason investigation. Special counsel Robert Mueller, as an arm of the Justice Department, and multiple congressional committees are currently investigating whether the Trump campaign colluded with the Russians.

"When [Trump Jr.] was approached with this idea, he should have turned it over to law enforcement immediately," Kaine said. "That's what anybody should have done."

NPR correspondent Geoff Bennett contributed to this report.

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