I saw a few headlines from more conservative news outlets about this. Mexico builds its own wall against migrants is the primary source but it's behind a paywall so I can't investigate on my own. Even if I was able to read the story, I'd want to see the story corroborated somewhere.
The claim (summarized in the Newsmax article Financial Times: US Gives Mexico $75M Aid for an Anti-Immigrant Wall) is that "the U.S. is sending Mexico $75 million in the form of equipment and training to help shore up its southern border." This would be to prevent migrants from Central American nations from entering Mexico, and the US would have an incentive to support it because those migrants would end up in the United States.
- Is a wall being built?
- Is "The US" sending money?
- Who in the United States is sending money?