National security adviser Mike Waltz is expected to depart from the Trump administration in the coming days, two sources familiar with the matter told CNN, the first major staff shakeup since the president took office in January.

Waltz was at the center of the Signal chat controversy, in which a journalist was accidentally included in a discussion of sensitive military information.

Waltz came under fire after he mistakenly included the editor of the Atlantic magazine in a Signal chat to discuss a military operation in Yemen.