Steve Bannon steps down from Breitbart News

— -- Stephen Bannon has stepped down as executive chairman of Breitbart News, the company announced in an online post and a source close to Bannon confirmed to ABC News.

The former White House chief strategist has faced mounting pressure to resign from Breitbart after he was quoted disparaging President Donald Trump and his family in a new book "Fire and Fury: Inside the Trump White House" by Michael Wolff. The Breitbart board started discussing his future at the company after the comments were revealed last week and continued debating it over the weekend, sources told ABC News.

One source close to Bannon, speaking on condition of anonymity, said he was essentially forced out. “He had to chose between Breitbart or his political activities. His political activities were hurting Breitbart,” the source said.

When reached by ABC News, Bannon declined to comment on the record.

Rebekah Mercer, a Breitbart shareholder and high-profile Republican donor, disavowed Bannon after his comments about the Trumps and favored his departure.

"She wasn't going to put real effort into Breitbart as long as he was there,” a source close to Mercer, speaking on condition of anonymity, told ABC.

In a rare public statement, she announced last week that she had cut Bannon off financially.

“She’s been on a warpath” against Bannon, another source close to Mercer told ABC News.

Bannon was forced out of the West Wing in August and returned to lead the media company where he had been executive chairman since 2012. He has told allies that he plans to continue his far-right political activities, and has raised money for a 501(c)4.

He released a statement on Sunday clarifying his comment that the June 2016 Trump Tower meeting with Donald Trump Jr, Jared Kushner and Russians was “treasonous," but stopped short of issuing a full-throated apology.

“I’m proud of what the Breitbart team has accomplished in so short a period of time in building out a world-class news platform," Bannon said in a statement Tuesday on the Breitbart website.

Breitbart CEO Larry Solov said, “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.”

Bannon has served as the far-right news site's executive chairman since 2012, taking a break in 2016 and 2017 to help run now-President Donald Trump's campaign and then serve in his administration.

The news was first reported by The New York Times and then was announced on Breitbart's news site.

The Breitbart announcement states that Bannon will be helping the company ensure "a smooth and orderly transition."

SiriusXM put out a statment saying "Breitbart News has decided to end its relationship with Stephen K. Bannon, therefore he will no longer host on SiriusXM since our programming agreement is with Breitbart News."