President Donald Trump on Thursday said Homeland Security Secretary Kristi Noem is leaving her post, and that she would be replaced by Sen. Markwayne Mullin, an Oklahoma Republican.

Noem’s departure from the Department of Homeland Security came after a wave of criticism of her management of the department and her handling of Trump’s immigration enforcement agenda, which saw two American citizens killed by federal agents in Minnesota in January.

Sen. Thom Tillis, R-N.C., during a hearing Tuesday where Noem was testifying, called her leadership of DHS a “disaster.”

“We’re an exceptional nation,” Tillis told her that day. “And one of the reasons we’re exceptional is we expect exceptional leadership. And you have demonstrated anything but that.”

At a hearing on Wednesday by the House Judiciary Committee, Noem, who is married, was asked if she has ever had sex with her top advisor, Corey Lewandowski, who is also married. She refused to answer, calling the question “tabloid garbage.”