Republican senate leadership is firing back at former Trump cheif strategist Steve Bannon after a report surfaced that he has a hit list of incumbents he and 'his allies' are planning to recruit primary challengers for.

"I wish they would focus on Democrats instead of Republicans," Sen. John Cornyn of Texas, the No. 2 Senate Republican, was quoted replying to Bannon in The Hill.

"It does [make it harder]. And it's not particularly productive. ...We ought to stay focused on the task at hand," added John Thune of South Dakota who is the Republican Conference chairman in the Senate.

The Senate leaders responded after Bannon disparaged his fellow Republicans in a highly anticipated interview with "60 Minutes," that aired on Sunday night. Bannon warned of a "civil war" within the party, claimed Republicans are at risk of losing the House of Representatives in 2018 and even slammed his former boss.

Bannon: McConnell told Trump to back off "Drain the Swamp" talk Credit: CBS

Cornyn added that Trump should lay off his criticism of Senate leadership as well saying, "The president's going to need as many friendly faces around here as he can get in order to get things done. I realize that bipartisanship is important, but he shouldn't mistake a smile for support when it really counts."

Bannon said during the interview that the firing of FBI Director James Comey may have been the biggest mistake in "modern political history."

The interview aired just hours before CNN reported that "Bannon and his allies" are planning to run primary challengers to establishment Republicans during the 2018 general election. The source went as far as disclose Bannon's hit list: Tennessee Senator Bob Corker, Mississippi Senator Roger Wicker, Alabama Senator Luther Strange, Nevada Senator Dean Heller and Arizona Senator Jeff Flake, the source said

Bannon confirmed he opposed President Donald Trump's decision to oust Comey, calling the FBI "an institution." Bannon told CBS that institutions such as the U.S. Senate and House of Representatives can be changed "if the leadership is changed." But he also said the FBI is different.

"I don't believe that the institutional logic of the FBI, and particularly in regards to an investigation, could possibly be changed by changing the head of it," Bannon said.

The ousted White House adviser also said that if Comey hadn't been fired, "We would not have the Mueller investigation," referring to special counsel Robert Mueller.

Bannon also weighed in on Republican infighting over the fate of immigrants brought illegally to the United States as children. Bannon said the issue could be so vitriolic that the party loses control of the U.S. House of Representatives next year.

Bannon, whose far-right views on immigration, climate and trade helped shape Trump's presidential campaign and his first months in office, was fired by the Republican president last month in a push to end factional fights within the White House.

Trump said last week he would scrap a program called Deferred Action for Childhood Arrivals, or DACA, that allowed the young immigrants to live and work in America.

Bannon supported ending the program, which had been put in place by Democratic former President Barack Obama.

Trump gave the Republican-controlled Congress six months to come up with an alternative, saying he would "revisit this issue" if lawmakers could not agree.

"I'm worried about losing the House now because of this," Bannon told CBS.

"If this goes all the way down to its logical conclusion, in February and March it will be a civil war inside the Republican Party," he said. "And to me, doing that in the springboard of primary season for 2018 is extremely unwise."

Republicans are divided over the Dreamers. Some believe they are illegal immigrants who are taking American jobs, while others say they contribute to the country and deserve compassion.

Bannon, who said he left the White House on his own terms, lashed out against "establishment" Republicans who have at times grappled with Trump, a real estate celebrity who had never before held elected office.

"The Republican establishment is trying to nullify the 2016 election," Bannon said, saying it was an "open secret on Capitol Hill" that many Republicans did not support Trump's agenda, and singling out Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan for criticism.

"They do not want Donald Trump's populist, economic nationalist agenda to be implemented,"Bannon said.

He called Republican national security officials who had served in the George W. Bush administration "idiots," including former secretaries of state Condoleezza Rice and Colin Powell, and former Vice President Dick Cheney.

"I hold these people in contempt, total and complete contempt," Bannon said, blaming them for U.S. trade problems with China and involvement in Iraq.

"They're idiots, and they've gotten us in this situation, and they question a good man like Donald Trump," Bannon said.