President Donald Trump has fired his National Security Adviser John Bolton.
Mr Trump tweeted on Tuesday that he told Mr Bolton on Monday night that his services were no longer needed at the White House.
He said Mr Bolton submitted his resignation on Tuesday morning.
Mr Trump tweeted that he “disagreed strongly” with many of Mr Bolton’s suggestions, “as did others in the administration”.
Mr Bolton, who was seen as one of the hawks in the administration, then gave his version of events with a tweet of his own.
He said: “I offered to resign last night and President Trump said, ‘Let’s talk about it tomorrow’.”
Mr Bolton also served in the administration of former president George W. Bush.