POTUS's speech today - are there Chinese troops in Mexico? Are they the invisible enemy? Doesn't sound like he is talking about the virus

"As you probably know, in Tijuana, various parts of Mexico, the COVID — it’s got about 24 names I can call it, from “COVID” to “China virus.” I can call it the “plague.” I call it the “China plague.” A lot of different names. But we always call it the “invisible enemy.” But the invisible enemy has been very tough on Mexico, and we have areas along the border where we’re in great shape because right there, because of that, that we’re in great shape. But on the other side, in Mexico, they’re suffering greatly with the virus. It’s been incredible what we’ve achieved. And we didn’t do the wall because of COVID; we did the wall because of security and drugs and other things. But it turned out that, in the middle of it all, along came this horrible plague."