After calling on Sen. Bob Corker (R-TN) to resign over his criticism of President Trump, former White House Chief Strategist Steve Bannon said he is starting a “coalition” to go after certain Republican members of Congress.

“We’re declaring war on the Republican establishment,” he said, appearing on Fox News’ “Hannity” Monday evening.

One of Bannon’s first targets is Corker, who is retiring next year. Bannon wants conservative Rep. Marsha Blackburn (R-TN), who just announced a Senate bid, to fill the seat.

“If Bob Corker has any honor, any decency, he should resign immediately. He should not let those words stand, what he said about the President of the United States,” Bannon said, referencing Corker calling the White House an “adult day care center.“

He said Republicans like Corker are the reason he left the White House and vowed to “go after them” in 2018.

“There’s a coalition coming together that’s going to challenge every Republican incumbent instead of Ted Cruz,” he said. “We’re spending a ton of time with grassroots organizations to make sure the people are fully vetted. … You are going to see real candidates and by the way, they’re going to take on incumbents in every state and they’re going to take on the Democrats after that.”

He said there will be about 15 names announced in the next several weeks of people who will be challenging incumbents, some of whom work in government and others who have served the Trump agenda as “outsiders.”

“We’re declaring war on the Republican establishment. … We’re going to cut off the oxygen to Mitch McConnell,” he said. “Mitch McConnell’s biggest asset is the money. We’re going to make it a liability. We’re going after them tooth and nail.”