U.S. President Donald Trump threatened former chief strategist Steve Bannon with legal action over ¡°defamatory¡± statements about Trump¡¯s son and son-in-law over a meeting with Russians during the 2016 presidential campaign.

Trump cut ties with Bannon on Wednesday, saying his former adviser had ¡°lost his mind¡± in a blistering statement issued after reports of disparaging comments by Bannon in a forthcoming book, ¡°Fire and Fury: Inside the Trump White House¡± by Michael Wolff.

In the book, Bannon described a June 2016 meeting with a group of Russians at Trump Tower in New York as ¡°treasonous¡± and ¡°unpatriotic.¡± The meeting, held after the Russians promised damaging information on Democratic presidential candidate Hillary Clinton, was attended by Donald Trump Jr., Trump son-in-law Jared Kushner and Paul Manafort, who was the campaign manager at the time.