MEXICO CITY (NYTIMES, WASHINGTON POST) - It has become a regular occurrence, particularly around the Easter holiday: scores or even hundreds of Central American migrants making their way north by foot and vehicle from the southern border of Mexico.
They include everyone from infants to the elderly, fleeing violence and poverty in their homelands.
They travel in large groups - the current is one of the largest at about 1,200 participants - in part for protection against the kidnappers, muggers and rapists that stalk the migrant trail, but also to draw more attention to their plight.
Some have the United States in mind, but many are only thinking as far as a new home in Mexico.
Called "caravans", most of the journeys, which date back at least five years, have moved forward with little fanfare, virtually unnoticed north of the border with the United States.
But tweets by President Donald Trump have suddenly turned the latest caravan into a major international incident and the most recent flashpoint in the politics of immigration in the United States.
"Getting more dangerous," the President tweeted on Sunday. "Caravans' coming."
On Monday, he warned that "our country is being stolen" by illegal immigrants, blaming Democrats for weak border policies and urging Mexico to strengthen its border enforcement.
"Mexico has the absolute power not to let these large 'Caravans' of people enter their country," he wrote in a tweet.
After days of walking from Mexico's southern border, the caravan of hundreds of migrants has now halted on a brown-grass soccer field, its participants unsure and anxious about the way forward.
The men and woman, most from Central America, were squatting Tuesday in a walled public park while government officials decide their fate.
"We are scared, just like you," Mr Irineo Mujica, the head coordinator of the migrant caravan, told the assembled group through a megaphone on Tuesday morning. "Now President Donald Trump has said that he wants to hit us with nuclear bombs."
Mr Trump has made the migrant caravan a central theme in his tweets for three days running - although he hasn't in fact threatened a nuclear strike. The President has warned that Mexico must stop the group or risk being penalised in the negotiations over reforming NAFTA. He has also threatened to reduce foreign aid to Honduras, the country of origin of many marchers.
On Tuesday, Mr Trump said he would call out the military to guard the border.
"We cannot have people flowing into our country illegally," Mr Trump said, as he discussed the caravan while posing for a photo at the White House with Baltic state leaders.
Earlier in the day, he tweeted: "The big Caravan of People from Honduras, now coming across Mexico and heading to our "Weak Laws" Border, had better be stopped before it gets there. Cash cow NAFTA is in play, as is foreign aid to Honduras and the countries that allow this to happen. Congress MUST ACT NOW!"
At the Victor E. Flores Morales sports park in this southern city in Oaxaca state, scores of children played on Tuesday on slides and metal swings, waiting for their parents and the organisers of this caravan to decide the next move. For most migrants, their goal is the United States, still more than 1,200km away. They wanted to march on.
Some said they heard about this caravan through friends and relatives; others said they have made the trip in the past but weren't allowed into the United States. The migrants said they had convened from several countries in Tapachula, a city along Mexico's southern border, and begun their march north.
A number of them said they were fleeing gang violence and extortion threats in their violence-plagued countries, while others said they were looking for better paying jobs.
After several nights of sleeping outdoors, the migrants had begun adapting to this bivouacked life. A former Pizza Hut employee from Guatemala boiled fish soup for the camp over a wood fire alongside his new friend, a fajita cook from El Salvador who had been deported after living in Texas for 14 years. A Honduran man who said he paid 60 per cent of his auto-mechanic salary in extortion fees to gang members still wore his orange vest from an overnight guard shift aimed at to preventing cell-phone theft.
On the surrounding streets, migrants begged for money.
All of those interviewed on Tuesday said that they would prefer to live in the United States but they would settle for Mexico if that was where they were allowed to stay.
Almost anything, they said, would be better than returning to Central America, which has some of the hemisphere's highest incidences of violence.
"There is a barbarous situation in our country," said Mr Santos Alberto Lino, 40, who had worked as an auto mechanic in Honduras before joining the caravan. "People want to live in peace and harmony."
Mr Trump's tweets have turned into fodder for the four candidates competing in the July 1 presidential election, with Mexican politicians rejecting his criticism of the country's response to the caravan.
But the Trump messages have caused a colossal headache for the Mexican government as it attempts to secure a NAFTA deal prior to the vote.
Mexican officials responded this week to Mr Trump's tweets as they usually do: politely, preferring not to inflame tensions with their northern neighbour. Mexico's chief technical negotiator on the trade deal, Mr Kenneth Smith Ramos, tweeted on Tuesday that the process of modernising the treaty "is entering a phase of intense activity".
Mexico, he added, "will continue working in a constructive manner".
The low-key Mexican government response to Mr Trump left the sense for some that the administration of President Enrique Peña Nieto had caved.
Mr Esteban Illades, editor of the Mexican magazine Nexos, said that the government "will definitely feel pressured to cave into Trump's demands".
In southern Mexico, many of the members of the migrant caravan knew that Trump had spoken harshly about them.
"Donald Trump's words are hurtful to us," said Mr Manuel Flores, 30, a Guatemalan who is one of the camp's self-appointed cooks. "We are not extraterrestrials, we are not from another world."
His friend, Mr Jose Ernesto, 28, from El Salvador, spoke about his time working in a Texas grillhouse for years before his deportation.
"You look in the kitchen and who prepared that food for you? It's a Mexican, it's a Hispanic," Mr Ernesto said. "We are the ones who have made your country the way it is." -
Mr Trump's comments have turned what had been an annual march to raise awareness about the suffering of migrants into something of a political crisis for Mexico. On Monday, Mexican immigration officials began to register the hundreds of migrants and talked about the possibility of humanitarian visas for the most vulnerable, while others might receive permits of less than a month. Some have already been deported, according to Mexican officials.
While the march wasn't unprecedented, this year's exercise drew an unusually large number of participants. Conservative American media jumped on the reports of march, depicting it as a sign of the threat of illegal migration to the United States. In fact, US border authorities reported a 26-percent decline in the number of people detained or stopped at the southern border in 2017 compared to the prior year.
In interviews on Monday, the caravan's organisers sounded frustrated, exhausted and dismayed.
"We are not terrorists," said Mr Mujica, Mexico director of Pueblo Sin Fronteras - People Without Borders - a transnational advocacy group that is coordinating the current caravan and has organised several others in recent years. "We are not anarchists. We try to help people to know their rights, things that we has human beings should be doing, try to advocate for human, sensible solutions."
But many of Mr Trump's admirers were seeing something very different: the spectre of the United States' borders overrun.
Mr Mujica was speaking by phone from Matías Romero, a town in the state of Oaxaca in south-west Mexico where the members of the caravan had spent the previous two nights, sleeping in a park.
The group left the southern Mexican border town of Tapachula on March 25, at that point numbering about 700. Most of the participants were from Honduras and many of them said they were fleeing violence and poverty in their home countries, organisers said.
Some say they were inspired to flee Honduras following the violent suppression of political protests in January.
Over the past week, the group grew in size, to about 1,200 by the time it arrived in Matías Romero.
But organisers said that contrary to the vision of a migrant onslaught on America conjured by Mr Trump, most participants do not intend to travel as far as the border of the United States.
"He's trying to paint this as if we are trying to go to the border, and we're going to storm the border," Mr Mujica said.
Mr Alex Mensing, project coordinator for Pueblo Sin Fronteras, added: "We're definitely not looking for some kind of showdown."
Mr Mujica predicted that 10 per cent to 15 per cent of the participants would seek asylum at the border. Most of the others would drop out along the way, many over the next several days as the group travelled from Oaxaca to the state of Puebla and on to Mexico City, and many of those would seek asylum or some other protection in Mexico.
In Puebla, Pueblo Sin Fronteras plans to hold workshops, led by volunteer lawyers, to teach migrants about their options for legal protections in the region, including in Mexico and the United States.
"We don't promote going to the United States," Mr Mensing said. "It's a challenging place to seek asylum."
In recent years, Mexico has become an increasingly attractive destination in its own right, not just a passageway for Central Americans and others seeking sanctuary from economic hardship and violence in their home countries.
"We have a lot of people living in Mexico now," Mr Mujica said, speaking of participants in past caravans. "All they want is a place to live without fear."
"We are trying - as Mexicans, as Americans - to find solutions," added Mr Mujica, a Mexican-American who holds dual citizenship.
In his Twitter posts on Sunday, Mr Trump also asserted that many migrants trying to cross the border into the United States were seeking to "take advantage of" the programme known as Deferred Action for Childhood Arrivals, or DACA, that has provided protected status to hundreds of thousands of young immigrants brought to the country as children.
Mr Trump announced last year that he was ending the programme, but was open to keeping it.
On Monday, advisers said that the President was also alluding to a perception, supposedly held by many Central American migrants, that as part of efforts to salvage DACA, Congress may soon agree to legislation that would permit unauthorised immigrants to remain in the United States.
But migrant-rights advocates, including coordinators of the latest caravan traversing Mexico, said these assertions were a White House invention.
"It's laughable!" Mr Mujica said. "Most of the people don't even know what DACA is. They know that it's almost impossible to get into the United States. They know that they're deporting everyone."
On Sunday, even Mexico's secretary of foreign affairs, Mr Luis Videgaray, weighed in, apparently in response Mr Trump's tweets that accused Mexico of lax immigration enforcement.
"Every day Mexico and the US work together on migration throughout the region," he wrote on Twitter. "Facts clearly reflect this. 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."
Mr Mensing said that the cross-country caravans originated in local protests inspired by the traditional Holy Week re-enactment of the Stations of the Cross.
Directors of migrant shelters and soup kitchens would conduct short, local marches along popular migration routes "as a way to highlight the kinds of things that would happen to migrants from Central Americans", including kidnappings, sexual assaults and murders, he said.
In recent years, these demonstrations got increasingly ambitious. In 2014, a caravan left the southeastern Mexican town of Tenosique, in the state of Tabasco, with a plan to go to Palenque in the state of Chiapas.
But the movement gathered momentum as it moved north and kept on going, Mr Mensing said.
It was the first caravan to reach the US border.