President Donald Trump on Monday unleashed a hostile tweetstorm on Sen. Richard Blumenthal, making a number of claims against the Connecticut Democrat, including that he had lied about serving in Vietnam.

Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist! — Donald J. Trump (@realDonaldTrump) August 7, 2017

Never in U.S.history has anyone lied or defrauded voters like Senator Richard Blumenthal. He told stories about his Vietnam battles and.... — Donald J. Trump (@realDonaldTrump) August 7, 2017

...conquests, how brave he was, and it was all a lie. He cried like a baby and begged for forgiveness like a child. Now he judges collusion? — Donald J. Trump (@realDonaldTrump) August 7, 2017

Trump's Twitter fusillade was apparently set off by Blumenthal's appearance on CNN earlier Monday in which he spoke about the investigation into the Trump campaign's alleged ties to Russia. "I think it's very important to protect and safeguard the independence and integrity of that investigation," Blumenthal said.

Later Monday, Trump suggested Blumenthal take a long vacation in Vietnam "so he can at least say he was there."

I think Senator Blumenthal should take a nice long vacation in Vietnam, where he lied about his service, so he can at least say he was there — Donald J. Trump (@realDonaldTrump) August 7, 2017

Let’s look at the facts:

What's true: Years ago, Blumenthal did misrepresent his military service, repeatedly conflating his time in the Marine Reserves in Washington, D.C., with those who served overseas in Vietnam. The idea that he was a Vietnam veteran became an accepted part of his biography.

"When we returned, we saw nothing like this," the senator said at a Connecticut rally in support of troops in 2003.

"We have learned something important since the days that I served in Vietnam," he said at another event in 2008.

In reality, the senator obtained at least five military deferments from 1965 to 1970, according to The New York Times’ 2010 expose that found Blumenthal had sometimes falsely claimed to have served in Vietnam; when he eventually enlisted in 1970, Blumenthal got a spot in the Marine Reserves, engaging in Washington drills and local projects like campground repairs.

He later apologized for misrepresenting his service, saying he regretted saying he’d served "in" Vietnam instead of "during" Vietnam.

What's not true: There’s no evidence that Blumenthal bragged — as Trump claimed in the tweets — about "battles" or "conquests" or cried when the scandal erupted during his Senate bid.

"No and no," a Blumenthal spokesman told NBC News on Monday when asked if the senator had bragged or cried.

Blumenthal himself hit back at Trump on Twitter, saying the president's "bullying" wasn't working.