PALM BEACH, Fla. (AP) — Threatening drastic action against Mexico, President Donald Trump declared on Friday he is likely to shut down America's southern border next week unless Mexican authorities immediately halt all illegal immigration. Such a severe move could hit the economies of both countries, but the president emphasized, "I am not kidding around."

"It could mean all trade" with Mexico, Trump said when questioned by reporters in Florida. "We will close it for a long time."

Trump has been promising for more than two years to build a long, impenetrable wall along the border to stop illeg...