President Donald Trump announced on social media that he is nominating former national security adviser Mike Waltz to serve as the U.S. ambassador to the United Nations. He added that Secretary of State Marco Rubio will take over as interim national security adviser. The announcement comes after it was reported earlier Thursday that Trump planned to remove Waltz as national security adviser. Waltz's deputy, Alex Wong, was also fired.

President Donald Trump's removal of Mike Waltz as national security adviser this week is the latest shakeup for an administration that just hit its 100th-day mark. Waltz, who served as national security adviser until Thursday, is now the United Nations ambassador nominee. Secretary of State Marco Rubio will fill in as acting national security adviser, Trump said. The move comes weeks after Waltz added a journalist to a Signal chat that was used to discuss military strikes.

President Donald Trump said Sunday that he plans to appoint a new national security advisor in about six months, telling reporters the former advisor, Mike Waltz, did not resign, but was instead tapped for an upgraded position as the administration’s ambassador to the United Nations. Trump spoke with reporters on Air Force One on Sunday night, where he was asked about several topics, including the trade deals, Mexican cartels and the national security advisor position. One reporter asked the president about Waltz’s exit as the national security advisor, which the president said he was being selected for what he called a “higher position,” or an “upgrade.”Trump also said Waltz did not make any mistakes, and, as the ambassador to the UN, he would do a good job.