President Donald Trump's ex-strategist is blasting White House aides who publicly distance themselves from the president's response to Charlottesville as well as the Roman Catholic Church.

Steve Bannon, in a CBS interview on 60 Minutes weeks after he was pushed out from the administration, criticized the Catholic Church, after church leaders denounced Trump's decision to end a program that protected hundreds of thousands of young immigrants from deportation.

He said bishops "need illegal aliens to fill the churches."

The bishops, Bannon said, "have an economic interest in unlimited immigration, unlimited illegal immigration.… This is not doctrine at all."

Kevin Appleby, who oversaw migration policies for the U.S. bishops for 16 years, said their position is, in fact, rooted in "2,000 years of church teaching."

"For them, this is ultimately a justice issue," said Appleby, now with the Center for Migration Studies, a think-tank and advocacy organization started by a Catholic religious order.

Self-described 'street fighter'

Bannon also singled out Trump economic adviser Gary Cohn for criticism in the interview, saying, "If you don't like what [Trump is] doing and you don't agree with it, you have an obligation to resign."

Cohn, in an interview with The Financial Times, had sharply denounced Trump for saying that "many sides" were to blame for the violence in Charlottesville, Va., and he criticized the administration's response to incident.

Bannon's take: "You can tell him, 'Hey, maybe you can do it a better way.' But if you're going to break, then resign. If you're going to break with him, resign."

Asked if Cohn should have quit, Bannon said: "Absolutely."

Bannon, a favourite among the farther-right in the GOP, was jettisoned from his post in August after a turbulent seven months in the West Wing. He returned to Breitbart News, which he led before joining Trump's campaign.

Calling himself a "street fighter," Bannon said "that's why Donald Trump and I get along so well. I'm going to be his wing man outside for the entire time."

Bannon's War44:56