(CNN) The chairwoman of the Republican National Committee on Thursday sent a warning to donors about the influential Koch political network, further fueling the fight between the powerful group and President Donald Trump and his allies.

The warning, presented in a memo to donors, comes amid days of open warfare between the Koch network and Trump Republicans after the President was criticized at the group's summer meeting.

In a memo to donors, RNC chairwoman Ronna McDaniel wrote that "some groups who claim to support conservatives forgo their commitment when they decide their business interests are more important than those of the country or Party."

"This is unacceptable," she added.

James Davis, a spokesman for the Koch network, said in a statement, "Just as we have in the past, we will work together with the President, elected officials and others where we agree. And, where we disagree, we will do so in a civil way. This is what it will take to make progress on the issues and ultimately create a society of mutual benefit -- where people succeed by helping others."

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