President Donald Trump has been using the supposed threat of migrant "caravans" to push Congress to fund his border wall -- but on Friday, even a Fox News reporter got him to admit that the wall would do nothing to stop them.

During a press gathering in the Oval Office, reporter John Roberts informed the president that his proposed wall would not actually prevent migrants from crossing into the United States given that it would be physically impossible for such a barrier to be built directly on the border, given that the actual U.S.-Mexico border is in the middle of the Rio Grande.

"There are all these tens of thousands of Central American migrants who just want to touch foot on U.S. soil and wait for the border patrol to pick them up," Roberts said. "How does building the new wall solve that?"

"You are right," the president admitted. "Touch the land, all of the sudden it's a catch-and-release deal. They go into the country, and in some cases, if they are criminals, they are released into our country. It's a ridiculous thing."

Despite Trump's claims, it is not the United States' policy to simply release known criminals who aren't legally in the country out into the general public.

Watch the video below.