Former Mexican President Vicente Fox has had a few choice words for US presidential candidate Donald Trump, prompting the brash billionaire to demand an apology.
Speaking on US television network Fusion, Mr Fox blasted the Republican frontrunner's campaign pledge to build a wall along the US Southern border and his promise to make Mexico pay for it.
"I am not going to pay for that f****** wall," Mr Fox told the network. "He should pay for it. He's got the money".
Mr Trump then used his Twitter account to decry the use of the "F word".
"He must apologize!" Trump tweeted. "If I did that there would be a uproar!".
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!
— Donald J. Trump (@realDonaldTrump) February 25, 2016
Mr Fox went on to call Mr Trump "crazy" and "egocentric" during his interview with presenter Jorge Ramos, who himself is no stranger to encounters with the property tycoon.
The former president also expressed concern about Mr Trump acquiring 46% of the Hispanic vote on his way to victory in the Nevada caucus earlier this week.
He said: "I'd like to know who those Hispanics are because they again, they're followers of a false prophet".
Mr Fox urged Hispanics and Latinos to "open your eyes", and said Mr Trump's policies are not rooted in Republican values.
Video contains strong language from the start
Mr Trump sparked outrage in the summer after he accused the Mexican government of allowing "rapists" and drug-runners to enter the US illegally.
Mexican President Enrique Pena Nieto's administration has referred to Mr Trump's remarks as "prejudiced and absurd".
On Thursday, US Vice President Joe Biden told Mexican officials in Mexico City that campaign rhetoric against immigrants was "dangerous" and "disturbing".
He said such views did not represent the vast majority of Americans.
Mr Trump, meanwhile, continues to hold a wide margin of support among Republican voters.
His win in Nevada was his third victory in a row, giving him solid momentum heading into the Super Tuesday contests on March 1st.
