(CNN)There’s little love lost between Ted Cruz and New York City.

On Friday, the feud between the Texas senator and America’s largest city escalated when the New York Daily News told Cruz, in bold, headline font on the front page of the paper: “Drop dead, Ted.”

“Hey Cruz: you don’t like N.Y. values? Go back to Canada!” the cover read.

Though Trump and Cruz have been jabbing each other on several issues for days, the Texas senator launched the first volley on this line of attack when he criticized Donald Trump for embodying “New York values” in an interview on a New Hampshire radio show. He repeated the attack throughout the week on Fox News and on the stage of the sixth Republican presidential debate Thursday night hosted by the Fox Business Network.

During Thursday night’s debate, Trump delivered a withering rebuke to Cruz’s attack, praising New York City’s resilience after 9/11.

“I saw something that no place on earth could have handled more beautifully, more humanely than New York,” Trump said. “The people of New York fought and fought and fought. We saw more death and even the smell of death and it was with us for months.”

“We rebuilt downtown Manhattan and everybody in the world watched and everybody in the world loved New York and loved New Yorkers,” he continued. “And I have to tell you, that was a very insulting statement that Ted made.”

Cruz defended his comments at the debate saying that the American people understood what he meant.

“I think most people know exactly what New York values are: socially liberal, pro-gay marriage, pro-abortion, focused on money and the media,” he said.

By Friday night, Cruz was featuring the Daily News cover in a fundraising pitch to supporters.

“It’s getting bad,” according to the email, which is signed by Cruz’s wife, Heidi. “Time is running short before the Iowa Caucus and we are being attacked from every angle by the liberal media. Look no further then the obscenity featured on this morning’s cover of the New York Daily News telling Ted to ‘Drop Dead!'”