Mexican President Enrique Peña Nieto speaks during a joint statement with Republican US presidential nominee Donald Trump in Mexico City on August 31. AP Photo/Dario Lopez-Mills Mexican President Enrique Peña Nieto said on Wednesday that Mexico would not be paying for Donald Trump's proposed wall along the southern border of the US after his meeting with the GOP presidential nominee.

"At the beginning of my conversation with Donald Trump I made it clear that Mexico would not pay for the wall," Peña Nieto tweeted.

Trump said earlier in the day that he and Peña Nieto didn't discuss who would pay for the wall — a key part of the real-estate mogul's immigration platform.

Hillary Clinton's campaign released a statement suggesting that Trump's meeting was a flop.

"It turns out Trump didn't just choke, he got beat in the room and lied about it," Hillary for America Chairman John Podesta said in the statement.

Read the full statement from Podesta here:

"Donald Trump has made his outlandish policy of forcing Mexico to pay for his giant wall the centerpiece of his campaign. But at the first opportunity to make good on his offensive campaign promises, Trump choked. What we saw today from a man who claims to be the ultimate 'deal maker' is that he doesn't have the courage to advocate for his campaign promises when he's not in front of a friendly crowd. We know who he is. After today's trip, we still know where Trump stands: an immigration plan that would deport 16 million people, end birthright citizenship, repeal DACA/DAPA and build a $25 billion wall and stick the American taxpayers with the bill."

Trump's position on immigration has been unclear since he made remarks that his stance could be "softened" after taking a strong stance on deporting millions of undocumented immigrants from the US.

The billionaire's campaign attempted to clarify in a statement late on Wednesday.

"Today was the first part of the discussion and a relationship builder between Mr. Trump and President Peña Nieto," Jason Miller, Trump's senior communications adviser, said.

"It was not a negotiation, and that would have been inappropriate. It is unsurprising that they hold two different views on this issue, and we look forward to continuing the conversation," he added.

The GOP candidate will deliver an immigration speech on Wednesday night in Phoenix, Arizona.