President Trump recently told senior adviser Stephen Miller that he’s “in charge” of his administration’s immigration policy, according to The Wall Street Journal. The recent shake-ups at the Department of Homeland Security, including Secretary Kirstjen Nielsen’s upcoming departure, reportedly stem from the president’s frustrations with how policies have been enforced at the department. Trump and Miller reportedly want to reinstate the zero-tolerance policy, which received immense backlash last year. Miller reportedly told officials at DHS and the Justice Department to “get in line” with the president’s policy vision. The administration is also reportedly looking to oust acting DHS Deputy Secretary Claire Grady in order to ensure Trump’s pick—U.S. Customs and Border Protection Commissioner Kevin McAleenan—takes control of DHS when Nielsen officially leaves later this week.

CNN reports Trump recently told border officials in Southern California to not allow migrants into the country because the U.S. doesn’t “have the room.” Along with Nielsen’s departure, the administration ousted Secret Service Director Randolph Alles and may force out the U.S. Citizenship and Immigration Services Director Lee Francis Cissna.