Asked at the meeting with Enrique Pena Nieto on the sidelines of the G20 summit in Hamburg, Germany, if he still wanted Mexico to pay for the wall, Trump said: 'Absolutely'.
Before that, both presidents delivered statements with Trump hailing the 'successful day' so far.
"We're negotiating NAFTA (the North American Free Trade Agreement) and some other things with Mexico and we'll see how it all turns out, but I think we've made very good progress," Trump said.
Pena Nieto, through a translator, said that the meeting will help the two countries continue a 'flowing dialogue', in particular "for the security of both nations, especially for our borders."
The Mexican president noted that 'migration' is an issue that has 'occupied' both administrations. He added that it was a "co-responsibility to deal with organised crime issues."
Building a wall between Mexico and the United States to stop illegal immigration and Mexico paying for it was one of Trump's key campaign pledges in last year's election.
The two leaders have since spoken by phone, and a series of high-level meetings have eased the tension.
Trump first met Pena Nieto in August 2016 when he was still a presidential candidate.
That visit turned into a public relations nightmare for Pena Nieto, who was lambasted for welcoming the brash Republican billionaire despite his insults and threats.
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