U.S. President Donald Trump is scheduled to travel to the U.S. - Mexico border Friday to view a border wall project, one day after backing down on a threat to shut down the southern border unless Mexico takes action to stop illegal migrant and drug traffic into the United States.

Trump will travel to Calexico, California on the southern border to tour a section of recently-installed fence. The administration says the fencing is part of the president's southern wall project and even put up a plaque to commemorate it, though the section of fence had been planned since 2009 and had been completed last year.

For almost two weeks, the president has been threatening to close the border, because, he said, Mexico was not doing enough to stop drugs and illegal immigration. Last week, he made it sound like a certainty:

'So there's a very good likelihood that I'll be closing the border next week and that'll be just fine with me,' Trump said.

But that proposal prompted a strong reaction, even from Trump's own party. U.S. Senate Majority Leader Mitch McConnell said it was a bad idea.

'Closing down the border would have potentially catastrophic economic impact on our country. And I would hope we would not be doing that sort of thing,' McConnell said.

Thursday, during a White House Cabinet meeting, Trump backed away from the immediate threat, saying instead, he would give Mexico a year to stop the flow of illicit drugs and surge of migrants to the United States or he would impose tariffs on cars it was exporting to the U.S.

So, we will put tariffs on if they don't apprehend, and ultimately we're going to give it period of time. But if in a year from now, drugs continue to pour in, we're going to put tariffs on,' Trump warned.

White House officials had tried to figure out a way that Trump could halt undocumented immigrants from entering the U.S. while not obstructing the flow of nearly $1.7 billion of goods and services crossing the border each day, along with nearly a half-million legal workers, students, shoppers and tourists.

Economists outside the government also predicted economic havoc, with Mark Zandi, the chief economist at Moodys Analytics, saying 'a full shutdown of the U.S.-Mexican border of more than several weeks would be the fodder for recessions in both Mexico and the U.S.