On Sunday, Trump unleashed a racist attack on four progressive congresswomen of color, telling them to “go back and help fix the totally broken and crime infested places from which they came.” The tweets were aimed at Congressmembers Ayanna Pressley, Alexandria Ocasio-Cortez, Rashida Tlaib and Ilhan Omar. All four are U.S. citizens, and three of the four were born in the U.S. Ilhan Omar was born in Somalia before coming to the U.S. as a refugee at age 12.

Congressmember Omar fired back at Trump, tweeting, “As Members of Congress, the only country we swear an oath to is the United States. Which is why we are fighting to protect it from the worst, most corrupt and inept president we have ever seen.” She added, “You are stoking white nationalism because you are angry that people like us are serving in Congress and fighting against your hate-filled agenda.”

Trump’s Twitter tirade also named House Speaker Pelosi. He wrote, “These places need your help badly, you can’t leave fast enough. I’m sure that Nancy Pelosi would be very happy to quickly work out free travel arrangements!” Nancy Pelosi called Trump’s remarks xenophobic and said that Trump’s tweet “reaffirms his plan to 'Make America Great Again' has always been about making America white again. Our diversity is our strength and our unity is our power.”

Trump’s racist attacks come on the heels of a public feud between Speaker Pelosi and the four congressmembers following last month’s passage of the contested border funding bill—opposed by the four. Last week, Pelosi told The New York Times, “All these people have their public whatever and their Twitter world. But they didn’t have any following. They’re four people, and that’s how many votes they got.” AOC tweeted in response: “That public 'whatever' is called public sentiment. And wielding the power to shift it is how we actually achieve meaningful change in this country.” She also said in an interview that Pelosi’s “explicit singling out of newly elected women of color” was “outright disrespectful.” Last week, Pelosi told the progressive congressmembers to bring any grievances to her in person rather than express them via Twitter.