(The Lion) — President Donald Trump announced Thursday that GOP Sen. Markwayne Mullin will replace Homeland Security Secretary Kristi Noem, marking the first Cabinet secretary to leave during Trump’s second term.

Effective March 31, Trump said Noem, who has “served us well,” will be “moving to be Special Envoy for The Shield of the Americas, our new Security Initiative in the Western Hemisphere.”

The Truth Social announcement came shortly after the Wall Street Journal reported that Trump was preparing to fire her. Trump’s final straw was when Noem faced a contentious Senate hearing earlier this week that indicated lawmakers on both sides of the aisle were growing frustrated with her, the Journal reported, citing advisors, and the president was angered by her more than $200 million ad campaign in which she was featured prominently.

Trump said Noem’s replacement, Mullin, will make “a spectacular Secretary of Homeland Security.”

“Serving 10 years in the United States House of Representatives, and 3 in the Senate, Markwayne has done a tremendous job representing the wonderful People of Oklahoma, where I won all 77 out of 77 Counties — in 2016, 2020, and 2024!,” Trump wrote on Truth Social. “A MAGA Warrior, and former undefeated professional MMA fighter, Markwayne truly gets along well with people, and knows the Wisdom and Courage required to Advance our America First Agenda.”

Trump added that he will work to “Keep our Border Secure, Stop Migrant Crime, Murderers, and other Criminals from illegally entering our Country, End the Scourge of Illegal Drugs and, MAKE AMERICA SAFE AGAIN.”

This story is developing.