Sen. Kamala Harris (D-Calif.) shared a blistering criticism of President Donald Trump’s ongoing attacks against a coalition of progressive lawmakers on Tuesday evening, saying his behavior “defiles” the White House and that he had taken the presidency to a “new low.”

“I think it’s un-American. It is unbecoming of the president of the United States,” Harris told CNN’s Kyung Lah. “I think it defiles the office of the president of the United States. It is irresponsible, it is hateful, it is hurtful and he has taken the presidency to a new low.”

She later said Trump “needs to go back where he came from and leave that office.”

Harris, a 2020 presidential candidate hoping to unseat Trump next year, was commenting on Trump’s feud with a squad of freshman Democrats in Congress, namely Reps. Alexandria Ocasio-Cortez (N.Y.), Ayanna Pressley (Mass.), Ilhan Omar (Minn.) and Rashida Tlaib (Mich.). On Sunday, Trump tweeted that such lawmakers should “go back” to other countries if they were dissatisfied with the state of things in America. All four are American citizens, and only Omar was born overseas: Her family emigrated from a Kenyan refugee camp when she was a child and she is originally from Somalia.