Reports say President Donald Trump will nominate National Security adviser Mike Waltz to become the nation's ambassador to the United Nations.

US National Security Adviser Mike Waltz is leaving his post with the Trump adminstration, according to media reports. Waltz, who was the president's principal adviser on national security issues, has had a difficult tenure amid accusations that senior officials used insecure methods of communication to conduct government business.

Waltz inadvertently added The Atlantic's editor-in-chief to a group thread discussing sensitive national security matters.