U.S. President Donald Trump exchanged derogatory tweets with Tennessee Senator Bob Corker of his own party Sunday.
Trump wrote that he had refused to endorse Corker for a re-election race which led the senator to drop out, saying Corker had "begged" for the endorsement.
"He is also largely responsible for the horrendous Iran Deal!" Trump wrote. "Hence, I would fully expect Corker to be a negative voice and stand in the way of our great agenda. Didn't have the guts to run!"
Corker shot back on Twitter minutes later.
"It's a shame the White House has become an adult day care center," he wrote. "Someone obviously missed their shift this morning."
Corker, chairman of the Senate Foreign Relations Committee, was a prominent supporter of Trump during his 2016 presidential campaign, but has become increasingly critical of his fellow Republican since his time in the White House.