Donald Trump threatened to close the United States’ border with Mexico next week, repeating a threat he has made numerous times before and angering Mexican leaders and business groups.

The president said on Twitter: “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 added: “This would be so easy for Mexico to do, but they just take our money and ‘talk.’ Besides, we lose so much money with them, especially when you add in drug trafficking etc.), that the Border closing would be a good thing!”

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Trump has long been adamant about the need for border security. He campaigned on the promise of construction of a wall on the US’s southern border to be paid for by Mexico and forced a government shutdown after Congress did not appropriate funds for it. Trump eventually yielded after the longest shutdown in American history and then declared a national emergency to unilaterally shift money to wall construction.

Mexico’s foreign minister, Marcelo Ebrard, reacted angrily to Trump’s latest statements. “Mexico does not act on the basis of threats. We are a great neighbor,” Ebrard said. “[Ask] the million and a half Americans who chose our country as their home, the largest community of [Americans] outside the US. For them we are also the best neighbor they could have.”

But speaking at a levee in Florida on Friday afternoon, Trump amplified the tweets, noting that a border closing would be retaliation for Mexico’s alleged failure to take action against Central Americans coming through the country to enter the United States. “Mexico is tough. They can stop them,” said Trump. “But they chose not to … If they don’t stop them, we’re closing the border.”

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However, Trump’s declaration came just a day after President Andrés Manuel López Obrador said his country was doing its part to fight migrant smuggling. “We are going to do everything we can to help,” López Obrador said. “We don’t in any way want a confrontation with the US government.”

Meanwhile, some business leaders warned a border shutdown would disrupt tourism and commerce between the United States and Mexico, which totaled $612bn last year, according to the US Census Bureau.

“We’d be looking at losses worth billions of dollars,” said Kurt Honold, head of CCE, a business group in Tijuana, Mexico. “It’s obvious he’s not measuring what he says.”

The threat to close the border reiterated statements that Trump had made at a rally in Michigan on Thursday night where he threatened to “close the damn border”.

Trump also said at the rally that asylum seekers from Central America were seeking to enter the United States under false pretenses. “It’s a con job,” he said.

Earlier on Thursday he tweeted that he “may close border” and threatened to do so in a number of tweets throughout 2018. This included an all capital letters threat in mid-October: “I must, in the strongest of terms, ask Mexico to stop this onslaught – and if unable to do so I will call up the U.S. Military and CLOSE OUR SOUTHERN BORDER!”

The tweets came as the homeland security secretary, Kirstjen Nielsen, wrote to Congress describing a “system-wide meltdown” due to the influx at the border. “DHS facilities are overflowing, agents and officers are stretched too thin, and the magnitude of arriving and detained aliens has increased the risk of life-threatening incidents,” said Nielsen.

The letter follows Kevin McAleenan, the commissioner of US Customs and Border Protection (CBP), saying that the system was at “a breaking point” while in El Paso, Texas. He said that CBP was dealing with a 30% increase in migrants seeking to enter the United States and estimated that the agency would apprehend 100,000 people in the month of March. This number included 40,000 children.

The result was that the agency was being forced to close highway checkpoints and to reassign inspectors from border crossings to deal with the crush of arrivals, McAleenan said. CBP was also releasing undocumented immigrants directly into the country because of a lack of facilities to detain them.

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