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Evan Vucci, Associated Press
President Donald Trump speaks about border security in the Oval Office of the White House, Friday, March 15, 2019, in Washington. Trump issued the first veto of his presidency, overruling Congress to protect his emergency declaration for border wall funding.

SALT LAKE CITY — President Trump threatened to close the southern border Thursday, saying that Mexico and other Central American countries were not doing enough to stem the tide of migrants crossing into the United States from Mexico.

This comes two days after U.S. Customs and Border Patrol detained 4,100 migrants on March 26 — the highest number of total detentions in one day at the border in more than a decade, according to The Washington Post.

Trump tweeted that Mexico is "doing NOTHING" to stop the flow of illegal immigrants, adding that "They are all talk and no action."

This isn’t the first time Trump has threatened to close the border: the president first said he would do so last November.

But this renewed vow to seal the border comes on the heels of a proclamation Wednesday by Kevin McAleenan, the commissioner of U.S. Customs and Border Protection, that the U.S immigration enforcement system along the nation’s southern boundary is “at the breaking point,” The Washington Post reported, and that authorities are releasing migrants into the country after cursory background checks because of the overwhelming number of families with children crossing the border seeking asylum.

“That breaking point has arrived this week,” McAleenan told The Washington Post. “CBP is facing an unprecedented humanitarian and border security crisis all along our southwest border, and nowhere has that crisis manifested more acutely than here in El Paso."

For the first time in a decade, U.S. Customs and Border Protection is “reluctantly” conducting direct releases of migrants: instead of turning them over to Immigration and Customs and Enforcement for detention or giving them ankle bracelets to track their whereabouts, the agency is releasing migrants with just a notice to appear in court, the Post reported.

According to McAleenan, U.S. Customs and Border Patrol detained more than 4,100 on March 26, the highest total detentions in one day at the border in more 10 years. The agency expects border apprehensions are on pace to exceed 100,000 this month — more than a 3 percent increase, according to The Washington Post. For context, in May 2014, at the height of the last border crisis, there were more than 68,800 migrants apprehended at the border, the newspaper reported.

The number of migrants coming to the border dramatically increased after President Trump reversed course on his “zero tolerance” immigration policy, announcing that parents and children would no longer be separated at the border, according to The Washington Post.

McAleenan postponed an appearance before Congress on Wednesday to travel to the border, Politico reported.

Trump’s threat to close the border also comes amid a battle over the national emergency he declared last month over border security. Trump seeks to shift billions of dollars from the Pentagon’s budget toward building a wall on the southern border, a key promise of his 2016 presidential campaign.

[Read more: [What President Donald Trump's national emergency declaration tells us about the state of American democracy]](https://www.deseretnews.com/article/900060281/what-president-donald-trump-national-emergency-border-declaration-tells-us-about-the-state-of-american-democracy.html)

Though both houses of Congress attempted to block the declaration, the emergency declaration is set to stand after Congress failed to override the president’s veto.

[Read more: Shutting down the internet, testing chemical weapons on people and 2 more alarming things President Donald Trump could do with national emergency powers_]_

Trump has previously accused El Salvador, Guatemala and Honduras of misuse of U.S. aid intended to improve economic conditions spurring migrants to cross the border in the first place, according to Politico. The president threatened to cut that aid off altogether in December.

More recently, earlier this week, Politico reported that confusion over Trump’s tweets about the three countries had stalled delivery of U.S. aid.

U.S. Homeland Security chief Kirstjen Nielsen traveled to Honduras Wednesday to address the issue, meeting with Northern Triangle government leaders to forge what she called “a HISTORIC agreement to confront the root causes of the crisis on our border.”

“Working with Central American govts to increase security & prosperity in the region has been one of my greatest priorities,” she said in a tweet, though she did not elaborate further.

In November, Trump implemented his controversial "Remain in Mexico" plan, which requires aslyum-seekers to remain in Mexico until their asylum status is granted.

(Read more: How Utah Sen. Mike Lee may have paved the way for Trump's new asylum plan)

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Before the plan was officially put into place, Utah Sen. Mike Lee traveled to Mexico and Guatemala to float the idea of such a plan with government officials in both countries, the Deseret News reported in November.

(Read more: Utah Sen. Mike Lee in Mexico, Guatemala seeking solutions to migrant caravan)

According to a July 2017 report by Human Rights First, migrants and refugees face “acute risks of kidnapping, disappearance, sexual assault, trafficking and other grave harms in Mexico.”

The American Civil Liberties Union will challenge the "Remain in Mexico" policy in federal court on Friday, according to NPR.