MEXICO CITY (AP) —The president of Mexico says Donald Trump wasn’t telling the truth when he described their Wednesday conversation.

Specifically, President Enrique Peña Nieto said that he and Trump did indeed discuss who would pay for construction of a massive wall on the U.S.-Mexico border. That’s the centerpiece of Trump’s immigration plan.

Trump and Peña Nieto met privately in Mexico City on Wednesday afternoon.

When they emerged from the meeting, Trump told reporters they discussed the wall, but not paying for it.

Hours later, Peña Nieto tweeted his version: “At the beginning of the conversation with Donald Trump, I made clear that Mexico would not pay for the wall.”

The Trump campaign did not immediately respond to a request for comment.