Trump told The Wall Street Journal that the United States' southern neighbor could end up funding the proposed structure on its border with the U.S. if the North American Free Trade Agreement gets tweaked.
"They can pay for it indirectly through NAFTA," he told the newspaper in an interview. "We make a good deal on NAFTA, and, say, I'm going to take a small percentage of that money and it's going toward the wall. Guess what? Mexico's paying."
It is unclear what mechanism would go into NAFTA that would cause Mexico to indirectly pay for the structure, which Trump promised as a candidate. Last year, the administration floated a possible 20 percent border tax on goods coming from Mexico, before walking back the idea.