President Donald Trump fired off a series of tweets Monday morning that took aim at Sen. Richard Blumenthal.

The tweets came shortly after the Democratic senator appeared on CNN, where he spoke about the ongoing investigation into Russian interference during the 2016 election.

The president, who is currently on vacation in New Jersey while the White House undergoes renovations, accused Blumenthal of defrauding voters by claiming he fought in Vietnam. He also called the senator a "con artist."

Blumenthal was a Marine Corps reservist during the Vietnam War era, but did not serve there. In 2010, he apologized for falsely saying he had served in the war.

Blumenthal responded to the president’s tweets by saying that bullying won't work and that "no one is above the law."

At a Monday news conference, Blumenthal focused on his new bipartisan legislation, which he says is needed to ensure the president does not attempt to fire Special Counsel Robert Mueller III. Mueller is investigating Russia's meddling during the election and whether there were any links to the Trump campaign.

Blumenthal says he does not think that his spat with the president will prevent the state from getting federal funding for things like infrastructure. The senator says he believes they can put their differences aside.

But later Monday afternoon, Blumenthal was still on the president's mind. Trump unleashed another tweet suggesting that Blumenthal take a "long vacation" in Vietnam, "so he can at least say he was there."