Republican presidential candidate Ted Cruz has asked for the resignation of his communications director, Rick Tyler, following the distribution of a video that falsely depicted his rival Marco Rubio dismissing the Bible.

Tyler apologized to the Florida senator Sunday night, calling the attack “inaccurate.”

The departure comes just two days after Cruz’s disappointing third-place finish in the South Carolina primary, and marks the highest-level staff shakeup to date for his campaign. It also reflects genuine concern among the Cruz camp that accusations of “dirty tricks” are beginning to stick and damage the Texas senator’s presidential prospects.

GOP front-runner Donald Trump was quick to promote that narrative following the news of Tyler’s firing:

Wow, Ted Cruz falsely suggested Marco Rubio mocked the Bible and was just forced to fire his Communications Director. More dirty tricks! — Donald J. Trump (@realDonaldTrump) February 22, 2016

Just saw the phony ad by Cruz - totally false, more dirty tricks. He got caught in so many lies - is this man crazy? — Donald J. Trump (@realDonaldTrump) February 22, 2016

Tyler, who had been a ubiquitous presence on the campaign trail, was scheduled to appear on MSNBC Monday afternoon, but abruptly left minutes before. He did not immediately return MSNBC’s request for comment, nor did Catherine Frazier, Cruz’s national press secretary.

Cruz told reporters Monday that Tyler was “a good man,” but that had asked for his resignation over the misleading video about Rubio.

“This was a grave error of judgment,” Cruz said. “It turned out the news story he sent around was false, but I’ll tell you, even if it was true, we are not a campaign that is gonna question the faith of another candidate. Even if it was true, our campaign should not have sent it. That’s why I’ve asked for Rick Tyler’s resignation because the standards of conduct in this campaign have been made absolutely clear for every member of the campaign.”

The video in question purportedly shows Rubio walking into a hotel lobby and telling Cruz’s staffer and father, Pastor Rafael Cruz, that there were “not many answers” in the Bible they were reading. Rubio’s communications director, Alex Conant, later said that the video had been transcribed incorrectly and that Rubio had actually told the Cruz staffer “all the answers” were in the Bible.

Close video Cruz Asks Spokesman To Resign Over Rubio Attack Ted Cruz asks for the resignation of his communications director, Rick Tyler, after Tyler posted a video on social media that appeared to show Marco Rubio saying something derogatory about the Bible. Ted Cruz asks for the resignation of his communications director, Rick Tyler, after Tyler posted a video on social media that appeared to show Marco Rubio saying something derogatory about the Bible. share tweet email Embed

The inaccurate version of the video was not widely disseminated; Tyler tweeted, then quickly deleted it Sunday afternoon. In fact, it wasn’t until after Rubio’s campaign accused Team Cruz of yet another dirty trick that the video grew legs.

Rubio told reporters Monday that Cruz should fire someone for what he called a “pattern” of “deceptive and untrue” tactics.

“We’re now at a point where we start asking about accountability,” said Rubio. “You talk about the VA, where people who aren’t doing their job need to be fired — well who’s going to be fired when Ted Cruz is president? Because this campaign now has repeatedly done things that they have to apologize for and no one’s ever held accountable.”

Conant, meanwhile, attributed the “culture” of lies and dirty tricks to Cruz, not Tyler.

“Rick is a really good spokesman who had the unenviable task of working for a candidate willing to do or say anything to get elected,” Conant told NBC News’ Gabe Gutierrez. “There is a culture in the Cruz campaign, from top to bottom, that no lie is too big and no trick too dirty. Rick did the right thing by apologizing to Marco. It’s high time for Ted Cruz to do the right thing and stop the lies.”

Since winning the Iowa caucuses earlier this month with about a third of the state’s Christian evangelicals – a victory he was hoping to repeat in the first-in-the-South GOP primary – Cruz has been under near constant attack for what his rivals call lies and dirty tricks. Cruz apologized to fellow White House hopeful Ben Carson after blasting out a report during the Iowa caucuses that suggested the retired neurosurgeon was suspending his campaign. Carson was, in fact, going home to Florida to get “fresh clothes” and believes he lost many votes to Cruz that night as a result of the misinformation.

Ahead of the caucuses, Cruz also attracted scorn for sending out mailers that suggested voters would get in trouble with the state if they failed to turn out. Iowa’s Secretary of State Paul Pate condemned the tactic, saying the mailer “misrepresents Iowa election law.”

Cruz faced similar accusations of dishonesty days before the South Carolina primary for releasing a photoshopped image of Rubio shaking hands with President Obama underneath the headline “The Rubio-Obama Trade Pact.” Todd Harris, senior adviser to Rubio, called the move “phony and deceitful.”

Separately, Trump began openly calling Cruz “a liar” and “the most dishonest” person in politics.

“You have to be very smart. You have to be very careful. You’ve got a very unstable guy in Cruz,” Trump warned a crowd in Mount Pleasant, South Carolina, last Monday. “He’s nuts.”

Whether Cruz lost to both Trump and Rubio in the Palmetto State expressly because of those attacks is unclear. But what’s certain is that Cruz’s third-place finish in a state where 73 percent of voters identified as evangelical, according to exit polls, put a serious dent in his strategy to head into the March 1 “SEC Primary” with the wind at his back.

“He’s certainly lacking momentum coming out of South Carolina,” said veteran Republican strategist Henry Barbour. “March 1 is definitely a make-or-break day for Ted Cruz and his campaign.”

Cruz, for his part, was all smiles following his narrow third-place finish Saturday night, telling “Meet the Press” host Chuck Todd hours later that he “had an incredible evening” and was seeing “conservatives continuing to unite” behind him. And to be sure, there are still many things to admire about Cruz’s play for the White House, such as his campaign organization, debate chops, fundraising capabilities and talent for staying on message. But if he can’t dominate in the South – particularly in his home state of Texas, which votes on Super Tuesday – his path to the nomination becomes dubious.

“His strategy was to capitalize on momentum from South Carolina going into the ‘SEC Primary,’” said Republican strategist Brian Walsh. “There’s no question that he underperformed in South Carolina and that the momentum he expected to be there does not appear to be there today.”

NBC News’ Vaughn Hillyard and Alex Jaffe contributed to this report.