Former White House chief strategist Steve Bannon is "going to war" with officials within the Trump administration, Axios reported Friday.

"He's going back to Breitbart News … he plans to go 'thermonuclear' is the word they're using against the more moderate elements of the White House, the ones that have come to be known as the globalists, the president's economic advisor Gary Cohn," Axios Executive Editor Mike Allen said a short time later in an interview with CNBC's "Power Lunch."

Axios first broke the story that Bannon's departure was imminent. On Friday, the White House released a statement saying, "White House Chief of Staff John Kelly and Steve Bannon have mutually agreed today would be Steve's last day."

The controversial Bannon helped power Trump into office. However, his populist ideas were at odds with others within the administration. On Wednesday, Reuters reported that discord between Bannon and national security advisor H.R. McMaster was destabilizing Trump's team.

Reporter Jonathan Swan, who broke the news for Axios, told CNBC's "Fast Money" on Friday that Bannon has "been at war" for a long time with the people in the White House that he considers globalists. That includes senior White House advisor Jared Kushner, Trump's daughter and advisor Ivanka Trump, and Cohn and McMaster, Swan said.

White House chief of staff John Kelly "came in with a mandate to put more order into the West Wing and he was told when he went around auditing the West Wing that Bannon was a major disruptive force in there," said Swan.

There was also probably one "mortal sin" that Bannon committed, Allen said.

"He crowded Donald Trump's spotlight. We know that's something that President Trump does not like."

The White House did not immediately respond to a request for comment.

Meanwhile, Breitbart senior editor-at-large Joel Pollak, who tweeted "#WAR" after Bannon's departure was announced, told CNBC on Friday that he meant Breitbart would go to war "rhetorically speaking," defending Americans against the mainstream media. He insisted Bannon's exit from the White House would not change Breitbart's coverage.

— CNBC's Jacob Pramuk and Fred Imbert contributed to this report.

WATCH: White House Chief Strategist Steve Bannon is out.