It all started Wednesday morning, when Fox in a CNN interview called Trump's visit a "political stunt." Fox added: "We don't like him. We don't want him. We reject his message."
Shortly after, Trump responded with a tweet, saying Fox had invited him to Mexico as well:
Former President Vicente Fox, who is railing against my visit to Mexico today, also invited me when he apologized for using the "f bomb."
Then Fox tweeted his response to Trump.
@realDonaldTrump, I invited you to come and apologize to all Mexicans. Stop lying! Mexico is not yours to play with, show some respect.
After meeting with Pena Nieto in Mexico, Trump is scheduled to travel to Arizona to deliver an evening speech designed to clarify his stance on immigration reform.