Trump knocks 'Da Nang Dick' Blumenthal after senator questions son's 'truthfulness'

President TrumpDonald John TrumpTrump watching 'very closely' as Portland braces for dueling protests WaPo calls Trump admin 'another threat' to endangered species Are Democrats turning Trump-like? MORE late Monday asked why Sen. Richard Blumenthal (D) is allowed to serve on the Judiciary Committee after the Connecticut lawmaker questioned whether the president's eldest son had been truthful in his testimony to Congress about his family's dealings with Russia.

"How does Da Nang Dick (Blumenthal) serve on the Senate Judiciary Committee when he defrauded the American people about his so called War Hero status in Vietnam, only to later admit, with tears pouring down his face, that he was never in Vietnam," Trump asked in a tweet.

"An embarrassment to our Country!" he added.

His tweet came minutes after Blumenthal told MSNBC's Rachel Maddow that he and other Democrats on the Senate Judiciary Committee had found "serious issues" with the "truthfulness" of Donald Trump Jr.Donald (Don) John TrumpHouse chairman warns foreign governments to 'cease and desist' spending money at Trump properties Chris Cuomo: 'I should be better than the guys baiting me' Trump Jr. dismisses conflicts of interest, touts projects in Indonesia MORE and other witnesses' closed-door testimony to the panel.

"I think many of them should be called back to testify in public and I hope that will be true of other congressional committees, as well, because behind closed doors, there was questions, serious issues concerning their truthfulness and that issue pertained particularly to Donald Trump Jr. in a number of contentions before our committee," Blumenthal said.

The president then resurfaced his frequently used "Da Nang Dick" nickname for the Democratic senator, who has faced questions in the past over his statements about to his military service.

The senator's own characterization of his service has differed in the past. In some statements, he claimed to have served "during the Vietnam era," while other statements are less ambiguous, including one statement in 2008 in which he said that he "served in Vietnam," according to The New York Times. He apologized in 2010, saying, "I have not been as clear or precise as I should have been about my service in the Marine Corps Reserves."

Blumenthal's office did not immediately respond to a request for comment from The Hill on Tuesday, but in the past has said that such tweets from the president are "not worth dignifying with a response."