Chief White House strategist Steve Bannon warned President Donald Trump that backlash would ensue if he fired James Comey as head of the FBI, according to a book excerpt published by New York Magazine.

“You can’t fire the FBI,” Bannon told Trump, according to an unnamed White House official cited in the report (adapted from an upcoming book by journalist Joshua Green).

According to Green, senior White House adviser and Trump’s son-in-law Jared Kushner disagreed with Bannon and pushed for Comey’s termination.

Trump’s abrupt firing of Comey in May led to former FBI director Robert Mueller’s appointment as special counsel to investigate Russian election meddling.

Bannon was prominent in the White House’s efforts to build a “war room” to keep up with and respond to the investigation.

According to Green, Bannon was responsible for skewing hiring toward lawyers rather than Trump’s favored publicists, and set the team up outside the White House so it would be free to “throw some fucking haymakers.”