The Republican National Committee says it's suspending its partnership with NBC News and its properties and won't allow the network to co-host a presidential primary debate scheduled for February.
The letter from RNC Chairman Reince Priebus to NBC News chief Andrew Lack comes after this week's heavily criticized debate on CNBC.
"The RNC’s sole role in the primary debate process is to ensure that our candidates are given a full and fair opportunity to lay out their vision for America’s future," Priebus said in the letter. "We simply cannot continue with NBC without full consultation with our campaigns."
Preibus said that Wednesday's CNBC debate "was conducted in bad faith. We understand that NBC does not exercise full editorial control over CNBC’s journalistic approach. However, the network is an arm of your organization, and we need to ensure there is not a repeat performance."
He said that the debate topics were to include such issues as "job growth, taxes, technology, retirement and the health of our national economy.
"That was not the case," he said. "Before the debate, the candidates were promised an opening question on economic or financial matters. That was not the case.
"Candidates were promised that speaking time would be carefully monitored to ensure fairness," Priebus added. "That was not the case. Questions were inaccurate or downright offensive.
"The first question directed to one of our candidates asked if he was running a comic book version of a presidential campaign, hardly in the spirit of how the debate was billed."
He accused the CNBC moderators of engaging in "gotcha" questions that were "petty and mean-spirited in tone, and designed to embarrass our candidates.
"What took place Wednesday night was not an attempt to give the American people a greater understanding of our candidates’ policies and ideas," Priebus said.
The RNC tells NBC it will still hold a debate as scheduled on Feb. 26 with its other planned media partner, National Review.
A spokeswoman for NBC News said, in a statement, "This is a disappointing development. However, along with our debate partners at Telemundo we will work in good faith to resolve this matter with the Republican party."
Even before the decision to break with NBC, several of the GOP campaigns had planned to meet to discuss complaints about how the party's debates are being run.
NBC could stand to lose major advertising revenue with the suspension of its debate broadcast rights.
The first Republican debate on Fox News, where moderators were also seen as aggressive, drew a record 24 million viewers. Wednesday's debate drew 14 million.
Candidates, faced with CNBC's questioning, lashed out on stage.
When moderator John Harwood interrupted New Jersey Governor Chris Christie as he attempted to answer a question, Christie shot back: "Even in New Jersey, what you're doing is called rude."
"This is not a cage match," added Senator Ted Cruz.
"And you look at the questions -- 'Donald Trump, are you a comic book villain?' 'Ben Carson, can you do math?'... 'Jeb Bush, why have your numbers fallen?' How about talking about the substantive issues people care about," he said to a loud roar from the crowd.
Cruz used the Republican outrage over the debate moderators to appeal to donors.
"I am declaring war on the liberal media," he began a fundraising email Friday.