US President Donald Trump says an explosive new book about the first year of his presidency is full of "lies, misrepresentations and sources that don't exist".
Trump was on Twitter the night before the release of "Fire and Fury: Inside the Trump White House" by Michael Wolff.
Trump didn't name Wolff, but said he "authorised Zero access to White House (actually turned him down many times)." Trump says he never spoke to the author.
Trump added, "Look at this guy's past and watch what happens to him and Sloppy Steve!"
That appears to be a reference to former White House strategist Steve Bannon, whom the book depicts as questioning Trump's competence and describing a June 2016 meeting between Donald Trump Jr., Trump campaign aides and a Russian lawyer as "treasonous."