In this file photo taken on December 12, 2018, a US Customs and Border protection vehicle passes by wall prototypes, as seen from behind the Mexico-US border fence in Tijuana, Mexico. - AFP

WASHINGTON:President Donald Trump threatened Friday to seal the US-Mexico border"entirely" if Congress does not approve billions of dollars infunding for a wall. In a burst of early morning tweets, the president said thealternative to funding his controversial wall project would be total separationfrom Mexico -- including making US car companies pull out their factories basedon the other side of the frontier.

The threat yetagain upped the ante in a political row that has led to a partial shutdown ofthe US government and seems set to dominate the start to the third year ofTrump's presidency. "We will be forced to close the Southern Borderentirely if the Obstructionist Democrats do not give us the money to finish theWall," Trump tweeted. Trump said he would then take US-Mexican relationsback to the days before the NAFTA agreement opened free trade across Canada,Mexico and the United States.

That would"bring our car industry back into the United States where itbelongs," he said. It was not clear how separating the two huge neighborswould work. Bilateral trade totaled an estimated $615.9 billion in 2017,according to US government figures. Neither did Trump make any mention of thenew free trade agreement, known as the USMCA, which he only recently signedwith the two neighboring countries to replace NAFTA and which he has repeatedlypraised as a huge boost for American commerce. In Mexico, President AndresManuel Lopez Obrador sidestepped Trump's threat, telling journalists: "Wedon't want to be imprudent and we don't think we should get into this."

$5 billionquestion

Trump wants $5billion in funding for a wall along the more than 2,000-mile border, which hesays is currently too porous to stop illegal immigration and which he claimshas become a magnet for criminals, drugs and even terrorists. Opponents --especially in the Democratic party but also some in Trump's Republican party --say that a physical wall is impractical and that the idea is being used as apolitical tool to whip up xenophobia in Trump's right-wing voter base.

Both sides havedug in. Democrats refuse to approve funding and the president -- who has madehardline immigration policies a centerpiece of his presidency -- has retaliatedby refusing to sign off on a wider spending bill, leaving some 800,000 federalemployees without pay. Negotiations on lifting that partial governmentshutdown, perhaps by providing some border security funding, have sputtered outand no new debate is scheduled before next Wednesday.

The president,who had already scrapped a Christmas visit to his Florida golf resort, has also"canceled his plans for New Year's," his incoming chief of staff,Mick Mulvaney, said on Fox News. Asked about the startling rhetoric, Mulvaneytold Fox that Trump "is trying to draw light to the fact this is a crazydiscussion to be having."

For oneRepublican Congress member, Brad Wenstrup, the paralysis over the wallreflected "a lot of political posturing. I would hope that it could beended soon," he told CNN television. "If you sit down and talk aboutthat, why is that such a hard thing to do?"

Caravan'invasion'

Experts aredivided on solutions to policing the long, often inhospitable border separatingthe world's biggest economy from the far poorer countries to its south.Although there is a huge cross-border drug trade and immigrants often enterillegally, others have genuine claims for asylum. Central Americans are alsodeeply integrated in the US economy, often performing physically demanding,low-pay jobs in construction, agriculture and other vital sectors.

Trump hasconsistently painted the asylum seekers and economic migrants in outlandishterms, raising the specter of rapists, gang members and people with infectiousdiseases roaming freely across the border. Trump has latched particularly on towhat have become known as the "caravans" -- groups of several hundredor even more migrants who make epic treks across Central America and Mexico totry to reach the United States.

According toTrump, the "caravans" amount to organized attempts at invading theUnited States. In one tweet Friday, Trump warned: "word is that a newCaravan is forming in Honduras and they are doing nothing about it." As aresult, he said, "we will be cutting off all aid" to El Salvador,Guatemala and Honduras. The impoverished, often dangerous countries have longreceived American assistance to boost democracy, human rights, education andsecurity. But according to State Department figures, the aid is alreadydropping steeply. Honduras is currently set to receive $65.7 million in 2019,down from $105.6 million in 2017, while Guatemala is slated for $69.4 million,down from $145 million. El Salvador received $88 million in 2017 and is setfor $45.7 millionnext year. - AFP