Donald Trump's old catchphrase was "you're fired" - and his senior team has had a very high turnover.
Read moreRex Tillerson
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Video caption: Tillerson bids farewell to 'mean-spirited' Washington In a speech to state department employees, outgoing Secretary of State Rex Tillerson advised staff to perform one act of kindness each day.
By Barbara Plett Usher
BBC state deparment correspondent, Washington
The new man running US foreign policy
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Video caption: Mike Pompeo is likely to take a tougher line on North Korea and Iran Mike Pompeo is likely to take a tougher line on North Korea and Iran, says Barbara Plett-Usher in Washington.
By BBC Monitoring
The world through its media
By Joel Gunter
BBC News
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Video caption: Tillerson sacking: Rex's aides never saw it coming either Rex Tillerson's adviser also had no idea his boss faced the axe judging by what he told the BBC last week.
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Video caption: Trump v Tillerson: A short history of disagreements Rex reportedly called the president 'a moron', while Trump sought to 'castrate' his secretary of state.
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Video caption: Rex Tillerson: 'I will now return to private life' Secretary of State Rex Tillerson responds after being fired by President Trump, reportedly via tweet.
BBC Minute: On Rex Tillerson
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Video caption: President Trump has fired his secretary of State - but the man himself didn't even know President Trump has fired his secretary of State - but the man himself didn't even know
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Video caption: Trump on Tillerson: I like Rex a lot, but we disagreed The president says goodbye to one Secretary of State and says he has 'total confidence' in the next.