Threatening drastic action against Mexico, President Donald Trump declared 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, Mr Trump said when questioned by reporters in Florida. "We will close it for a long time."

President Trump has been promising for more than two years to build a long, impenetrable wall along the border to stop illegal immigration, though Congress has been reluctant to provide the money he needs. In the meantime, he has repeatedly threatened to close the border, but this time, with a new surge of migrants heading north , he gave a definite timetable.

A substantial closure could have an especially heavy impact on cross-border communities from San Diego to South Texas, as well as supermarkets that sell Mexican produce, factories that rely on imported parts, and other businesses across the US.

The US and Mexico trade about $1.7 billion in goods daily, according to the US Chamber of Commerce, which said closing the border would be "an unmitigated economic debacle" that would threaten 5 million American jobs.