WASHINGTON ― Sen. Thom Tillis (R-N.C.) condemned comments made by President Donald Trump’s senior adviser Stephen Miller about Greenland on Wednesday, calling them “stupid,” “amateurish” and “absurd.”

“Some people around here call me cranky. You know what makes me cranky? Stupid,” Tillis said in a fiery speech on the Senate floor. “What makes me cranky is when people don’t do their homework.”

“I’m sick of stupid,” he added. “The amateurs who said it’s a good idea [to invade Greenland] should lose their jobs.”

Miller told CNN earlier this week that Greenland belongs to the United States, predicting that no one would oppose the U.S. militarily should it stake a claim to the semiautonomous territory that belongs to Denmark, a NATO ally.

Tillis’ remarks amount to a direct attack on a presidential aide so powerful he’s often referred to as Trump’s prime minister and a sharp escalation in the retiring senator’s occasional criticisms of the administration.