As sources on Thursday confirmed Mike Waltz’s exit from his post as national security adviser, the impact of the U.S. government group chat leaks known as Signalgate, continues to expand.

National security advisor Mike Waltz is expected to step down on Thursday in the first shake-up among the president’s top advisors.,The development, reported first by CBS News, comes just over a month after Waltz faced a barrage of criticism for adding The Atlantic editor Jeffrey Goldberg to a groupchat on Signal in which cabinet officials discussed war plans for a strike in Yemen.

The Trump loyalist faced scrutiny over a Signal chat he organized that mistakenly included The Atlantic journalist Jeffrey Goldberg.