- Former Mexican President Vicente Fox is having a public feud with Donald Trump
- Fox said during a live interview with Maria Bartiromo on Fox Business Network on Friday morning
(CNN)Former Mexican President Vicente Fox really doesn't like Donald Trump's proposed border wall.
So much, in fact, that for the second time in two days, Fox used an expletive -- this time, on live TV -- to describe it.
"I have to say that we are not, I am not going to pay for that f***ing wall," Fox said during a live interview with Maria Bartiromo on Fox Business Network on Friday morning, repeating the phrase that made waves when he used it a day earlier.
This time however, the expletive went uncensored as a visibly stunned Bartiromo gasped.
"I am not. And he should know that. And I am not going to apologize," Fox added.
Fox first made the inflammatory comments in an interview with Fusion's Jorge Ramos that was published Thursday, prompting Trump to demand an apology on Twitter and during a CNN debate Thursday night.
"FMR PRES of Mexico, Vicente Fox horribly used the F word when discussing the wall. He must apologize! If I did that there would be a uproar!," Trump wrote on Twitter.
Trump has often insisted that he will build a wall along the border and convince Mexico to pay for it. The promise is a staple of his campaign and has often been turned into a call-and-response at his rallies, where he asks supporters who will pay for the wall and they yell back, "Mexico!"
Fox was president of Mexico from 2000-2006.