The president said he would replace Kristi Noem, the homeland security secretary, with Senator Markwayne Mullin, after Ms. Noem was grilled by Republicans at a congressional hearing.
The homeland security secretary, who was fired by President Trump Thursday, helped fulfill his border pledges, but also drew negative attention to his administration.
Homeland Security Secretary Kristi Noem pushed back against her department’s inspector general, who told Congress in a letter that she had “systematically obstructed” his office’s work.
The Homeland Security Department’s inspector general, Joseph V. Cuffari, testifying last year. Mr. Cuffari has opened investigations that include an audit of how Immigration and Customs Enforcement investigates use-of-force incidents.
Mr. Bovino, who was the face of the Trump administration’s immigration crackdowns in American cities, was reported to have made disparaging comments in reference to the U.S. attorney in Minnesota, who is an Orthodox Jew.