Former US Secretary of State Rex Tillerson on Monday vehemently denied claims by former UN ambassador Nikki Haley that he worked to undermine President Donald Trump's agenda as part of a larger effort to "save the country".

In a new book, which will be released on Tuesday and of which excerpts were published on Sunday, Haley claims Tillerson and then-White House Chief of Staff John Kelly told her to resist some of Trump's instructions.


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