Mexican President Enrique Peña Nieto has reportedly canceled a planned trip to visit the White House after a "testy" phone call with President Donald Trump over a proposed wall along the U.S.-Mexico border, The Washington Post reported.

"One Mexican official said Trump 'lost his temper.' But U.S. officials described him instead as being frustrated and exasperated, saying Trump believed it was unreasonable for Peña Nieto to expect him to back off his crowd-pleasing campaign promise of forcing Mexico to pay for the wall," the Post said.

Peña Nieto had demanded that Trump publicly state that Mexico would not be paying for the wall — reneging on a promise Trump made throughout the 2016 presidential campaign. Trump said no. Neither man would budge on his position during the 50-minute phone call, so the Mexican president canceled his trip.

The move is political, as Peña Nieto faces a re-election bid in July. If he was seen as caving to Trump's demand, he would face a tough time with voters and supporters in his Institutional Revolutionary Party.

The two presidents’ public posturing over the wall — Trump demands that Mexico pay for it; Peña Nieto insists that it will not — has harmed their personal relationship and jeopardized the alliance between their neighboring countries.

“The problem is that President Trump has painted himself, President Peña Nieto and the bilateral relationship into a corner,” said Arturo Sarukhan, a former Mexican ambassador to the United States. “Even from the get-go, the idea of Mexico paying for the wall was never going to fly. His relationship with Mexico isn’t strategically driven. It’s not even business; it’s personal, driven by motivations and triggers, and that’s a huge problem. It could end up with the U.S. asking itself, ‘Who lost Mexico?’ ”

Still, negotiations between their respective administrations continue apace on the North American Free Trade Agreement and other issues. And both governments have strived to portray their ties as strong and the exchanges between their leaders as smooth.

In a readout of the phone call provided by the White House, there was no mention of any dispute. Instead, the White House said "President Trump underscored his commitment to expanding cooperation between the United States and Mexico on security, trade, and immigration."

This is the second time the visit of a leader from America's southern neighbor has not followed through on a trip. In January 2017, Trump told Peña Nieto he wouldn't meet with him if he was going to say that Mexico would not pay for the wall. Instead, in that phone call Trump urged Peña Nieto to say, "We will work it out."

"The fact is we are both in a little bit of a political bind because I have to have Mexico pay for the wall — I have to," Trump said, according to the Post. "I have been talking about it for a two-year period, and the reason I say they are going to pay for the wall is because Mexico has made a fortune out of the stupidity of U.S. trade representatives."