President Donald Trump's national security adviser Michael Waltz is expected to leave his post, sources familiar with the decision told ABC News Thursday.

This move comes as President Trump has been increasingly frustrated by Waltz after he came under intense scrutiny for inadvertently adding a reporter to a Signal chat.

The White House and Waltz have not commented on the moves. Sources cautioned the move is not final until Trump announces it.

The president is expected to announce the changes soon, according to sources.

This is a developing story. Please check back for updates.