Steve Bannon, the last electoral campaign adviser of US President Donald Trump and former White House chief strategist, resigned Tuesday as executive chairman of the ultraconservative media company Breitbart News following the anger he provoked in the president over the last few days.

Bannon has been the object of Trump's ire since extracts of the book "Fire and Fury" by author Michael Wolff were leaked, in which the former chief strategist described as "treasonous" and "unpatriotic" a 2016 meeting between the president's son Don Jr. and a Kremlin-linked lawyer.

The book, which went on sale last Friday despite attempts by Trump's lawyers to block it, compiles remarks by people in the president's inner circle, including Bannon, and reveals how he began to question Trump's fitness to occupy the Oval Office.

According to The New York Times, Bannon was forced to leave the chairmanship of the online Breitbart News because of the pressure applied by its wealthy financial patron, Rebekah Mercer, in reaction to the opinions he had voiced to the book's author.

After learning of his former chief strategist's remarks, 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 has publicly begged pardon for his participation in "Fire and Fury," which quickly became a bestseller, but his apologies were not welcome at the Oval Office.

"I don't believe there is any way back for Mr. Bannon at this point," White House spokesman Hogan Gidley said.

After his time as the president's adviser and strategist, Bannon has prospered until now as a stout defender of Trump's populist agenda from outside the White House.

He is also immersed in a battle against the candidates of the Republican establishment in this year's legislative primaries.

"Steve is a valued part of our legacy, and we will always be grateful for his contributions, and what he has helped us to accomplish," Breitbart CEO Larry Solov said in a farewell statement.