U.S. President Donald Trump on Sunday said on Twitter that there will not be a deal on legalizing the status of young adult immigrants known as Dreamers, declaring that the U.S.-Mexico border is becoming more dangerous.

After posting a "Happy Easter" message on the social media platform, Trump followed with: "Border Patrol Agents are not allowed to properly do their job at the Border because of ridiculous liberal (Democrat) laws like Catch & Release. Getting more dangerous. 'Caravans' coming. Republicans must go to Nuclear Option to pass tough laws NOW. NO MORE DACA DEAL!"

DACA (Deferred Action for Childhood Arrivals) is the program created in 2012 under Democratic President Barack Obama that Trump sought to rescind last autumn. Designed for individuals brought to the United States as children by parents who were undocumented immigrants, the program shielded the individuals from deportation and gave them work permits.

These big flows of people are all trying to take advantage of DACA. They want in on the act! —@realDonaldTrump

He also threatened to kill the North American Free Trade Agreement, which is currently being renegotiated with Mexico and Canada.

Mexico is doing very little, if not NOTHING, at stopping people from flowing into Mexico through their Southern Border, and then into the U.S. They laugh at our dumb immigration laws. They must stop the big drug and people flows, or I will stop their cash cow, NAFTA. NEED WALL! —@realDonaldTrump

Trump is spending the Easter holiday in Palm Beach, Fla., at his Mar-a-Lago resort. He told reporters on his way into Easter services that "Mexico has got to help us at the border."

Trump has said he was open to brokering a deal with congressional Democrats who want to protect the DACA program in exchange for funding to build a U.S.-Mexico border wall, a frequent campaign trail promise. He insisted during his presidential campaign that Mexico would pay for the wall.

'Not the pinata'

Mexico's presidential front-runner Andres Manuel Lopez Obrador launched his campaign close to the border on Sunday, demanding respect for Mexicans and signaling he may take a harder line toward Trump if he wins the July 1 election.

"Mexico and its people will not be the pinata of any foreign government," Lopez Obrador said in a speech in Ciudad Juarez, Mexico, which borders El Paso, Texas. "It's not with walls or use of force that you resolve social problems."

Although Trump threatened a veto last month of an omnibus spending bill because it did not address the fate of Dreamers and did not fully fund his border wall, he did sign the bill.

In the months after Trump took office, the number of apprehensions of undocumented migrants along the U.S.- Mexico border dropped dramatically, from more than 42,400 arrests in January 2017 to a low of around 15,700 in April, according to data from U.S. Customs and Border Protection. Since then, the number of arrests has risen and in the first months of 2018 was above the levels seen during the Obama administration.

'Caravan' heading for U.S.

His DACA tweets came shortly after a report on the Fox News Channel's Fox & Friends program, one of Trump's favourites, that a "caravan" of mostly Honduran migrants was crossing Mexico and headed to the United States, "either illegally or by asking for asylum."

More than 1,000 would-be migrants have passed through Mexico's southern states of Chiapas and Oaxaca in recent days in a so-called "refugee caravan" organized by U.S.-based immigrant advocacy group Pueblo Sin Fronteras.

In the town of Ixtepec, more than 1,500 men, women and children from Honduras, El Salvador and Guatemala waited in a sweltering warehouse on Saturday, mattresses rolled and bags packed, as local authorities and immigration officials from Mexico's federal government organized 15 buses to take them to their next stop on the long journey north.

U.S. President Donald Trump suggested on Twitter that he will scrap NAFTA in order to stop Mexico's 'drug and people flows' across the border. (Chip Somodevilla/Getty Images)

By travelling together, the immigrants hope to protect themselves from the crime and extortion that makes the route through Mexico dangerous. They say some, but not all, of them will seek asylum if they reach the United States.

Gina Garibo, a member of Pueblo Sin Fronteras travelling with the migrants, said the group would hold a meeting to discuss Trump's statements on Sunday and stressed that the caravan's aim was to protect vulnerable people.

"The main people here are fleeing criminal violence, political violence, in their country and this allows us to save

lives," she said in response to Trump's comments.

A guest on Sunday's Fox & Friends show, Brandon Judd, head of the National Border Patrol Council union, said undocumented migrants benefit from the "catch and release" program that Trump referenced in his tweet. Under it, they can be freed while awaiting court hearings if detained in the United States.

Petitioning for asylum

If recent border crossers do not claim asylum, they can usually be deported quickly. But if they say they fear targeted violence or persecution in their home countries, they can begin the long process of petitioning for asylum in immigration court.

In such instances, the government can choose to release those individuals while their cases are processed. Trump and his attorney general, Jeff Sessions, have often criticized the Obama administration for routinely parolling asylum seekers.

Border Patrol Agents are not allowed to properly do their job at the Border because of ridiculous liberal (Democrat) laws like Catch & Release. Getting more dangerous. “Caravans” coming. Republicans must go to Nuclear Option to pass tough laws NOW. NO MORE DACA DEAL! —@realDonaldTrump That situation has changed: last month, the American Civil Liberties Union filed a class-action lawsuit on behalf of nine plaintiffs alleging that U.S. Immigration and Customs Enforcement officers were now detaining almost all adults who seek asylum at a port of entry.

On Sunday Trump continued to criticize Mexico on Twitter saying Mexico is doing "very little, if not NOTHING," to stop the flow of people across the southern border.

"They laugh at our dumb immigration laws. They must stop the big drug and people flows, or I will stop their cash cow, NAFTA. NEED WALL!"

Last week, U.S. Trade Representative Robert Lighthizer expressed optimism that negotiations to modify NAFTA to terms more favourable to the United States were making progress and that a deal in principle could be reached quickly.

The thorniest issues in the NAFTA talks with Mexico and Canada concern U.S. demands on automotive trade and dispute settlement systems. Linking the future of the 24-year-old trade deal to Trump's border wall plan has never been among U.S. negotiating objectives.

Mexican Foreign Minister Luis Videgaray said the United States and Mexico work together on migration every day.

"An inaccurate news report should not serve to question this strong cooperation. Upholding human dignity and rights is not at odds with the rule of law. Happy Easter," he said in a tweet.

Mexico deported some 80,000 people in 2017, down from about 160,000 in 2016, official statistics show. The vast majority were from Central American nations. The drop reflects fewer Central Americans crossing the country last year.