Fox News has blasted Republican candidate Donald Trump over his "sick obsession" with female anchor Megyn Kelly.
Trump has been taking potshots at Kelly since she dared to bring up his long history of insulting women while moderating the first Republican debate last August.
"You've called women you don't like fat pigs, dogs, slobs and disgusting animals," she said.
"Your Twitter account has several disparaging comments about women's looks. You once told a contestant on Celebrity Apprentice it would be a pretty picture to see her on her knees. Does that sound to you like the temperament of a man we should elect as president?"
Trump was so incensed at Kelly's treatment of him that he feuded with her for months afterwards, labelling her a "lightweight" reporter, retweeting comments calling her "bimbo" and infamously implying she'd only asked that question at the debate because she was menstruating.
"I just don't respect her as a journalist," he said. "I have no respect for her, I don't think she's very good, I think she's highly overrated.
"She gets out and she starts asking me all sorts of ridiculous questions, and you could see there was blood coming out of her eyes. Blood coming out of her wherever."
Trump boycotted the second Fox News debate on the eve of the Iowa caucuses in January after failing to get Kelly removed as a moderator. He also skipped a town hall forum hosted by the Fox anchor in February, which every other Republican candidate attended.
In recent days, Trump has escalated the feud even more, repeatedly criticising "crazy Megyn" on Twitter and calling her a "second rate" reporter who's "unwatchable" and "biased" against him.
You get the picture. Fox News is standing by Kelly, a former corporate lawyer who joined the network as a reporter in 2004 and has gone on to become America's most-watched female news anchor. Fox released a strongly worded statement condemning Trump yesterday.
"Donald Trump's vitriolic attacks against Megyn Kelly and his extreme, sick obsession with her are beneath the dignity of a presidential candidate who wants to occupy the highest office in the land," Fox News said.
"Megyn is an exemplary journalist and one of the leading anchors in America - we're extremely proud of her phenomenal work and continue to fully support her throughout every day of Trump's endless barrage of crude and sexist verbal assaults.
"As the mother of three young children, with a successful law career and the second-highest rated show in cable news, it's especially deplorable for her to be repeatedly abused just for doing her job."
Trump's campaign responded to Fox with an equally strong statement, which echoed the candidate's previous attacks.
"Megyn Kelly is a highly overrated reporter and anchor that constantly disparages Mr Trump with negative and inaccurate reports," the campaign said.
"Despite the fact that he wants nothing to do with her and will not appear on her show due to her extremely biased reporting, much of the program is about him anyway on a nightly basis. In fact, Fox News has begged Mr Trump to do a prime time special to be broadcast on the Fox Network, not cable, with Megyn Kelly. He turned them down.
"On the Fox debate that Mr Trump did not do, they received by far their lowest ratings. Unlike Megyn Kelly, who resorts to putting out statements via Fox News, Mr Trump will continue to defend himself against the inordinate amount of unfair and inaccurate coverage he receives on her second-rate show each night."
A source familiar with that alleged "prime time special" has told Politico no one from the network asked Trump to appear in it.
Kelly and Trump have only confronted each other in person once since August, at the Republican debate in Detroit earlier this month. Trump ran headlong into Kelly while trying to bat away attacks over Trump University - a self-help school he founded that former students are now suing, claiming it was a scam.
"We (Trump University) have a 98 per cent approval rating. We have an A from the Better Business Bureau and people like it," Trump said. Kelly jumped in to check his facts.
"The rating from the BBB was a D-, and it was a result of a number of complaints they received," she said. "There's a class action of 5,000 people." She then read from an appeal court decision with some forthright language.
"The victims of con artists often sing the praises of their victimisers until they realise that they have been fleeced," the decision read.
Trump could only respond: "Give me a break. Let's see what happens in court."
Trump is still the clear frontrunner in the race for his party's presidential nomination, and the political climate keeps getting uglier. Today, protesters blocked a highway in Phoenix, Arizona in an attempt to stop supporters from reaching one of the candidate's rallies.
About two dozen protesters parked their cars in the middle of the road, unfurling banners reading "Dump Trump" and "Must Stop Trump" and chanting "Trump is hate". Traffic was backed up for kilometres.
The road was eventually cleared and protesters marched down the highway to the rally site, weaving between Trump supporters who booed and jeered them.
"Learn to speak English," one Trump supporter shouted at the protesters. "You can't even show your face," another pro-Trump attendee said to a protester with a bandanna over her face.
Arizona is the next major state to vote in the presidential nominating contest. The winner of its primary on Tuesday will receive all 58 of the state's delegates to the Republican national convention.
Demonstrators also took to the streets in Manhattan, marching on Trump Tower with a heavy police presence keeping them in check.
"Donald Trump, go away, racist, sexist, anti-gay," they chanted.