Threatening drastic action against Mexico, President Donald Trump declared 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 emphasised, “I am not kidding around.”

“It could mean all trade” with Mexico, Trump said when questioned  Friday 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 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 USD 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.

Trump tweeted Friday morning, “If Mexico doesn’t immediately stop  ALL illegal immigration coming into the United States through our  Southern Border, I will be CLOSING the Border, or large sections  of the Border, next week.”

He didn’t qualify his threat with “or large sections,” stating:  “There is a very good likelihood I’ll be closing the border next  week, and that is just fine with me.”

He said several times that it would be “so easy” for Mexican authorities  to stop immigrants passing through their country and trying to enter  the US illegally, “but they just take our money and ‘talk.’”

Homeland Security Secretary Kirstjen Nielsen suggested Trump was  referring to the ongoing surge of mostly Central American families  heading north through Mexico.

Many people who cross the border illegally ultimately request asylum  under US law, which does not require asylum seekers to enter at an  official crossing.

Short of a widespread shutdown, Nielsen said the US might close  designated ports of entry to re-deploy staff to help process parents  and children.

Ports of entry are official crossing points that are used by residents  and commercial vehicles.

“If we have to close ports to take care of all of the numbers who  are coming, we will do that,” Nielsen said.