President Donald Trump removed National Security Adviser Mike Waltz on Thursday and named Secretary of State Marco Rubio as his interim replacement. The move marks the first major staff shake-up since Trump took office in January.

In a post on Truth Social, Trump said he would nominate Waltz to be the U.S. ambassador to the United Nations (U.N.). “Mike Waltz has worked hard to put our Nation’s Interests first. I know he will do the same in his new role,” Trump wrote.

“Rubio will serve as National Security Advisor, while continuing his strong leadership at the State Department. Together, we will continue to fight tirelessly to make America, and the world, safe again,” The president added.

Waltz confirmed the news later, writing on X: “I’m deeply honored to continue my service to President Trump and our great nation.”

I’m deeply honored to continue my service to President Trump and our great nation. pic.twitter.com/FFTPjnIYkI

— Mike Waltz (@MikeWaltz47) May 1, 2025

Waltz had seen his support within the administration erode in recent weeks, largely due to his role in a March incident in which a journalist was inadvertently included in a group chat discussing sensitive military plans. 

Waltz’s nomination to the U.N. role still needs Senate confirmation. 

With his latest appointment, Rubio now holds four positions: secretary of state, national security adviser, national archivist, and acting United States Agency for International Development administrator.