One of the top officials overseeing President Donald Trump’s immigration crackdown, U.S. Homeland Security Secretary Kristi Noem, will leave her role, U.S. President Donald Trump said on Thursday, a major staffing move that raises questions about the direction of the Republican President’s immigration agenda.

“I am pleased to announce that the Highly Respected United States Senator from the Great State of Oklahoma, Markwayne Mullin, will become the United States Secretary of Homeland Security (DHS), effective March 31, 2026,” Trump wrote on Truth Social.

Noem will serve as “Special envoy for The Shield of the Americas,” Trump said.

Noem, a former governor of South Dakota, became one of Trump’s most high-profile Cabinet secretaries with social media posts that portrayed immigrants in harsh terms, highlighting cases of alleged criminal offenders and using vitriolic language. She faced criticism in January when she quickly labelled two U.S. citizens fatally shot by federal immigration agents in Minneapolis as committing “domestic terrorism.”