Temper tantrum.

Via Yahoo News:

Mexican President Enrique Peña Nieto said Thursday he has canceled an upcoming meeting with President Trump amid a spat over Peña Nieto’s refusal to pay for a planned wall along the U.S. southern border. Trump has long vowed that Mexico would pay for the construction project.

“This morning we informed the White House that I will not attend the scheduled work meeting for next Tuesday with @POTUS,” Peña Nieto announced on Twitter.