Donald Trump has fired his Secretary of State Rex Tillerson saying they disagreed on the Iran nuclear deal.
The president has chosen CIA director Mike Pompeo to be his new secretary of state.
Mr Trump said he and Mr Tillerson “disagreed on things” and cited their differing opinions on the Iran nuclear deal.
Iran agreed before Mr Trump took office to curb its nuclear programme in exchange for the easing of economic sanctions.
The president regularly criticises the agreement as a bad deal and has repeatedly threatened to end it.
He spoke on Tuesday of his desire to break the deal, but noted that Mr Tillerson “felt a little bit differently, so we were not really thinking the same”.
Mr Trump tweeted that Mr Pompeo, “will do a fantastic job!” and thanked Mr Tillerson for his service.
He said he made the decision to sack his secretary of state “by myself” and suggested Mr Tillerson will be “much happier now” .
Mr Pompeo is strongly opposed to the Iran nuclear deal, and Mr Trump said they have a “very, very similar thought process”.
The undersecretary of state for public diplomacy, Steve Goldstein, said Mr Tillerson “had every intention of staying” in the job because he felt he was making critical progress in national security.
Two White House officials have said Mr Tillerson was told he was out on Friday, but Mr Goldstein said he “did not speak to the president and is unaware of the reason”.
Hours later, Mr Goldstein was himself fired.
Mr Tillerson had returned from a shortened trip to Africa hours before Mr Trump’s announcement, which offered no explanation for the change.
A White House official said Mr Trump wanted to have a new team in place before upcoming talks with North Korea and various trade negotiations.
There had been rumours throughout most of Mr Tillerson’s tenure of friction between Mr Trump and his secretary of state, a former ExxonMobile chief executive.
In October, NBC news reported that Mr Tillerson called the president a “moron,” something he never actually denied.
Mr Tillerson continued to insist his relationship with the president was solid and brushed off rumours of strain between them.
He was due to retire from Exxon in March 2017 aged 65 under the company’s mandatory retirement policy, and was paid 27.3 million dollars (£19.5 million) last year,