Former Mexican President Vicente Fox is taking to Twitter to again blast President-elect Donald Trump over his repeated promises to have Mexico pay for a wall at the U.S.-Mexico border, while Trump is again lashing out at some of his favorite targets.

The latest exchange of unpleasantries comes amid media reports that members of the Trump transition team were urging congressional Republican leaders to take steps to appropriate funds for the border wall, a move that CNN -- one of Trump’s favorite objects of scorn -- described as a maneuver that “would break a key campaign promise.”

Trump uses Twitter to again bash the media

CNN’s coverage and reporting from other news outlets on the topic prompted yet another angry tweet from the president-elect, with Trump bashing the media, while also pledging that Mexico will reimburse the U.S.

for any money it spends to start building the wall.

Vicente Fox uses profanity in tweet

Trump’s tweet didn’t go unnoticed south of the border, where Fox responded with a tweet of his own, using a profanity to push home his point that Mexico wouldn’t be paying for a border wall.

“TRUMP, when will you understand that I am not paying for that f----n wall,” the tweet said. “Be clear with US taxpayers. They will pay for it.”

The tweet from Fox on Friday followed a similar message -- but without an obscenity -- that he posted on Thursday.

Fox, Trump have been at odds for months

Fox and Trump have been at odds for months, with Fox using the “F” word in the past in declaring that Mexico would not be paying for the border wall -- a wall that would stretch hundreds of miles and cost billions of dollars.

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Fox did issue an apology last year over his use of profanity, but he has since also compared Trump to Hitler and to deceased Cuban dictator Fidel Castro.

Meanwhile, before he even takes office the president-elect has been claiming a number of victories in keeping jobs in the U.S., while also threatening to levy heavy taxes on companies that move jobs overseas.

Earlier this week Ford announced it was canceling plans for a new plant in Mexico, a move that means the work would be done by about 700 U.S. workers instead. Trump lauded the decision, saying there would be more similar decisions in the future. But he also warned Toyota over a "big border tax" when it announced this week that it would open a plant in Mexico that would build cars for sale in the U.S.