President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE's former White House chief strategist Stephen Bannon is warning Republican candidates not to take money from the conservative Koch network — or face consequences.

"You take Koch money, it's going to be toxic," Bannon told CNBC in an interview. "We are going to let people know that if you take Koch money there's a punishment.

"If you take money from people who are against the president and are looking to put a knife in the back of the president, you are going to pay."

ADVERTISEMENT

Bannon's comments came amid signs of tensions between the Koch network and President Trump.

The Koch network has said it would freeze out Republicans who break with its fiscally conservative policy priorities, at least for now, and that it plans to back only a handful of candidates in Senate races in Florida, Wisconsin, Tennessee and Missouri.

The Koch network, a web of conservative groups funded by billionaire industrialist Charles Koch, has long been a forceful player in conservative politics in the U.S. This election cycle, the network is slated to spend about $400 million on politics and policy initiatives.

But it has broken with President Trump and some of his allies in Congress on issues such as spending and government trade. And the Koch network declined to endorse Rep. Kevin Cramer Kevin John CramerAbortion stirs GOP tensions in Supreme Court fight Momentum growing among Republicans for Supreme Court vote before Election Day On Paycheck Protection Program, streamlined forgiveness is key MORE (R-N.D.), who is challenging Sen. Heidi Heitkamp Mary (Heidi) Kathryn HeitkampHarris faces pivotal moment with Supreme Court battle Centrists, progressives rally around Harris pick for VP 70 former senators propose bipartisan caucus for incumbents MORE (D) for her Senate seat in North Dakota.

The announcement drew the ire of President Trump, who said in a tweet on Monday that the network had become a "total joke" and insisted that he "never sought their support because I don’t need their money or bad ideas."

Bannon declined to say in his interview with CNBC exactly how he planned to go after the Koch network, but asserted that it needed to be held accountable.

"Let's start holding the Kochs accountable. It's a con job and they are a total scam," he told the network. "They are promoters and it's a total Ponzi scheme. They never raise as much money as they talk about and no one ever knows who their donors are."