Former White House chief strategist Steve Bannon said he's certain that Donald Trump Jr. brought attendees of the June 2016 Trump Tower meeting to meet his father.
"The chance that Don Jr. did not walk these Jumos up to his father's office of the 26th floor is zero," Bannon told author Michael Wolff.
Bannon's comments appear in Wolff's "Fire and Fury: Inside the Trump White House," which is based on more than 200 interviews with the president and members of his staff. The book will be published Jan. 9 by Henry Holt. NBC News obtained a copy of the book ahead of its release.
In a statement, President Donald Trump said: "Steve Bannon has nothing to do with me or my Presidency. When he was fired, he not only lost his job, he lost his mind."
Bannon is also quoted in the book saying the meeting was "treasonous" and "unpatriotic."
Attendees of the meeting included Russian lawyer Natalia Veselnitskaya and other Russians. Trump was reportedly in Trump Tower on June 9, the day of the meeting.
Bannon joined the Trump campaign team two months after the meeting.
Bannon was ousted from the White House in August after seven months as an influential operative known to have the president's ear. He has reportedly remained in contact with Trump since leaving the administration.
An attorney for Trump Jr. did not respond to a CNBC request for comment.
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