Story highlights Trump's digs are a reference to Blumenthal's past misrepresentations about his military service

Trump has lashed out against Blumenthal before

Washington (CNN) Connecticut Sen. Richard Blumenthal called President Donald Trump out on Twitter for "bullying" after a Twitter attack from the President accused the senator of lying and being a "phony Vietnam con artist."

"Empaneling the grand jury shows that Bob Mueller is pursuing this potential wrongdoing by the Russians, the attack on our democracy, seriously and diligently -- and there is no minimizing or underestimating that attack by the Russians," Blumenthal said. "It was purposeful and relentless, and it involved propaganda and hacking into our voting machines or at least an attempt to do it and potential collusion by the Trump campaign and then obstruction of justice. That investigation must be pursued."

Trump responded to Blumenthal's comments on Russia in a tweetstorm just minutes later.

"Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist!"

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