Former Mexican President Vicente Fox voiced his outrage towards Donald Trump's supporters and criticized the GOP frontrunner's plans if he wins the United States presidency.

Fox to Trump: We're Not Paying

In an exclusive interview earlier this week with Univision and Fusion journalist Jorge Ramos, Fox responded to Trump's plan of building a wall on the U.S.-Mexican border.

"I'm not going to pay for that f**king wall! He should pay for it. He's got the money," Mexico's former leader said.

Asked by Ramos if he's afraid that Trump would be the next U.S. president and what this could mean to Mexico, Fox said in the interview that "democracy cannot take that." He, however, admitted that he was worried when Trump won 44 percent of the Hispanic votes in the Nevada caucus.

"I'd like to know who those Hispanics are," Fox added, noting that they could be "followers of a false prophet" who is neither a Republican nor a Democrat, but an "egocentric" man.

Fox warned that Hispanics are "wrong" if they think they are going to benefit from a Trump presidency.

"Please, you Hispanics, Latinos in the U.S., open your eyes. It's not to defend our race. Not to defend our creed. It's to defend this very same nation that is hosting you. This nation is going to fail if it goes into the hands of a crazy guy," he added.

Trump responded to Fox via Twitter and demanded an apology from the former president for using foul language while discussing his proposed wall. Trump, who is known for his profane-filled campaign speeches, estimated that the wall would cost around $8 billion.

More Politicians Criticize Trump

Fox wasn't the first Mexican president to slam Trump. Earlier this month, Fox's successor, Felipe Calderón, said in an interview with CNBC that Mexico's people would not pay for Trump's "completely useless" and "stupid" wall.

Calderón stressed that closing the borders would be a huge trade loss for the U.S. He also expressed his disappointment that an admirable society like America yielded a candidate like Trump, who he said is "not very well-informed."

In his visit to Mexico City, U.S. Vice President Joe Biden offered an apology for the anti-immigrant rhetoric made during the presidential campaign trail. He insisted that such comments do not represent the American people.

Biden, who was in Mexico for economic discussions, called the remarks "disturbing" and "incredibly ill-advised." Biden has been opposed to the cruel rhetoric about undocumented immigrants since the 2016 presidential campaign began.