Former President of Mexico Vicente Fox is bashing Donald Trump’s visit with Mexico’s current President Enrique Peña Nieto, ahead of the Republican nominee’s speech on immigration in Pheonix, Arizona.

“I don’t understand what’s going on here, and I really apologize for our president taking this step forward,” Fox stated, expressing criticism of Nieto for agreeing to Trump’s visit to Mexico. “I really expect from him, as all 130 million Mexicans, all of our great brother Mexicans in the United States, an explanation from both, from President Peña and Trump himself.”

Trump reacted to Fox’s criticism on Twitter Wednesday morning, pointing out that Fox had previously invited Trump to Mexico in May.

Former President Vicente Fox, who is railing against my visit to Mexico today, also invited me when he apologized for using the "f bomb." — Donald J. Trump (@realDonaldTrump) August 31, 2016

During an interview with Breitbart News roughly three months ago in California, Fox extended an invitation to Trump to visit Mexico after he apologized for using vulgar language against Trump’s proposal to build a wall along the southern border.

“I apologize. Forgiveness is one of the greatest qualities that human beings have, is the quality of a compassionate leader. You have to be humble. You have to be compassionate. You have to love thy neighbor,” Fox stated in May during an interview with Breitbart News at the J.W. Marriott in Santa Monica, California.

“I don’t think he should follow the strategy of attacking others, offending others, to get to his purpose. There are other ways and means of doing it,” Fox stated at the time. “I invite him to come to Mexico and to see what Mexico is all about.”