Republican presidential candidate Donald Trump reignited his on-again, off-again feud with Fox News by posting several attacks against anchor Megyn Kelly to his Twitter account. In response, Fox's anchors, hosts, and its chairman and CEO pushed back, and are now demanding an end to Trump's attacks and an apology in a new press release.

The first round of the Fox-Trump dispute came after the candidate criticized Kelly for what he characterized as hostile questions during the Fox Republican presidential debate, going so far as to accuse her of having “blood coming out of her wherever” during the event.

After that controversy, Fox head Roger Ailes issued a release stating that he and Trump “had a blunt but cordial conversation and the air has been cleared.”

Trump continued to make disparaging marks about Kelly, however, claiming that Kelly was off-air during her vacation due to his initial clash with her. Fox denied the charge and called it a conspiracy theory.

On August 24, Trump once again returned to attacking Kelly, writing, “I liked The Kelly File much better without @megynkelly. Perhaps she could take another eleven day unscheduled vacation!” He added that Kelly “must have had a terrible vacation, she is really off her game,” noting that she had “no clue on immigration” and criticizing her interview with Dr. Cornel West.

Trump also posted several tweets from fans attacking Kelly, including one that called Kelly's show “a waste of an hour on Fox,” and another that referred to her as “the bimbo.”

In response, many Fox personalities took Trump to task.

Fox & Friends host Brian Kilmeade called Trump's attacks “unwarranted-unacceptable;” America's Newsroom host Bill Hemmer tweeted, “Easy, Mr. Trump;” Fox senior meteorologist Janice Dean wrote that it was “unpresidential,” and The Five co-host Dana Perino praised “the intelligence, class & grace” of Kelly.

Special Report host Bret Baier told Trump “this needs to stop,” while Sean Hannity added, “Focus on Hillary, Putin, border, jobs, Iran China & leave @megynkelly alone.” The network's senior political analyst Brit Hume asked if Trump was a “seven-year-old” for the tone of his comments.

Even more Fox figures chimed in, including contributors like Katie Pavlich, Julie Roginsy, Jedediah Bila and Kirsten Powers.

These tweets were followed by an August 25 press release from Ailes:

“Donald Trump's surprise and unprovoked attack on Megyn Kelly during her show last night is as unacceptable as it is disturbing. Megyn Kelly represents the very best of American journalism and all of us at Fox News Channel reject the crude and irresponsible attempts to suggest otherwise,” Ailes statement reads. “I could not be more proud of Megyn for her professionalism and class in the face of all of Mr. Trump's verbal assaults. Her questioning of Mr. Trump at the debate was tough but fair, and I fully support her as she continues to ask the probing and challenging questions that all presidential candidates may find difficult to answer,” Ailes said. “Donald Trump rarely apologizes, although in this case, he should. We have never been deterred by politicians or anyone else attacking us for doing our job, much less allowed ourselves to be bullied by anyone and we're certainly not going to start now. All of our journalists will continue to report in the fair and balanced way that has made FOX News Channel the number one news network in the industry.”

On the Fox daytime program Happening Now, anchor Jon Scott read the entire statement on-air.

The statement was also posted on Fox Nation and at the top of Fox's online election page.

Trump quickly replied:

“I totally disagree with the FOX statement. I do not think Megyn Kelly is a quality journalist. I think her questioning of me, despite all of the polls saying I won the debate, was very unfair. Hopefully in the future I will be proven wrong and she will be able to elevate her standards to a level of professionalism that a network such as FOX deserves. ”

Former Fox contributor and editor of the Weekly Standard Bill Kristol had a different point of view. Appearing on Newsmax TV, Kristol said Trump's comments were “excessive” but Fox shouldn't be too “thin-skinned.” He noted Trump was likely to “antagonize” Megyn Kelly fans who he would probably prefer to have on his side.

Despite the flare-ups, Fox and Trump have had a symbiotic relationship. His frequent appearances on the network, particularly on Fox & Friends, made the former reality TV star into a political figure, and since he decided to run for the presidency, Fox has featured him far more often than any other candidate.

The network also defended Trump after he attacked Sen. John McCain's war record in July, and after his recent use of the racially-charged term “anchor baby.”