The President of Mexico was scheduled to meet with President Trump next week, but the meeting was cancelled after Mexican President Enrique Peña Nieto stated he would not be paying for a border wall to be erected between Mexico and the United States. The border wall has been a cornerstone of Trump’s campaign for months, and this clash with Mexico was almost guaranteed to happen at some point.

CNBC reports on the new era of twitter diplomacy:

Pena Nieto was expected to visit the U.S. next week to discuss immigration and trade issues, and Mexican officials have been meeting with the Trump administration ahead of time. Though Trump seemed to make conciliatory comments about Mexico on Wednesday, the president reversed that sentiment by tweeting Thursdaythat the meeting should be canceled if Mexico won’t agree to pay for the wall.

The Mexican president tweeted back, in Spanish, that he informed the White House that he would not be attending the meeting. White House spokesman Sean Spicer later said that the wall could be paid for with a 20 percent tax on all imports from Mexico, but the White House later backtracked and said the 20 percent tax was just an example of what could be done.

Here are the tweets which started the confrontation:

To which Nieto eventually responded with this:

Roughly translated:

This morning we have informed the White House that I will not attend the meeting scheduled for next Tuesday with the @POTUS.

Apparently there had been several high level meetings between Trump administration officials and individuals from within the Mexican government, and those meetings will continue. This visit next week would have marked the first formal meeting between the two Presidents since Donald Trump’s inauguration last week.

As a result of the cancellation, the Mexican Peso took a hit, according to CNBC:

Twitter diplomacy just ripped the Mexican peso, again.

At its low, the currency was down more than a percent against the U.S. dollar after Mexican President Enrique Pena Nieto canceled a meeting with President Donald Trump, in a dispute over Trump’s border wall. It later reversed some of the losses.

Mexico certainly needs the United States as a trading partner and an economic partner, there’s no question about that. Nieto is stuck with some low approval ratings in Mexico, and capitulating to Trump on this matter would probably send that even lower. At this point, it’s a matter of national pride that Mexico continues standing up to Trump’s continued claim that our southern neighbor will pay for the border wall.

If you recall, Trump and Nieto did meet back in August of last year, so the two men do have somewhat of a working relationship.