NEW YORK (NYTIMES) - In shelters from Kansas to New York, hundreds of migrant children have been roused in the middle of the night in recent weeks and loaded onto buses with backpacks and snacks for a cross-country journey to their new home: a barren tent city on a sprawling patch of desert in West Texas.
Until now, most unauthorised children being held by federal immigration authorities had been housed in private foster homes or shelters, sleeping two or three to a room. They received formal schooling and regular visits with legal representatives assigned to their immigration cases.
But in the rows of sand-coloured tents in Tornillo, Texas, children in groups of 20, separated by gender, sleep lined up in bunks. There is no school: The children are given workbooks that they have no obligation to complete. Access to legal services is limited.
These midnight voyages are playing out across the country, as the federal government struggles to find room for more than 13,000 detained migrant children - the largest population ever - whose numbers have increased more than five-fold since last year.
The average length of time that migrant children spend in custody has nearly doubled over the same period, from 34 days to 59, according to the Department of Health and Human Services, which oversees their care.
To deal with the surging shelter populations, which have hovered at near 90 per cent of capacity since May, a mass reshuffling is underway and shows no signs of slowing. Hundreds of children are being shipped from shelters to West Texas each week, totalling more than 1,600 so far.
The camp in Tornillo operates like a small, pop-up city, about 56km south-east of El Paso on the Mexico border, complete with portable toilets. Air-conditioned tents that vary in size are used for housing, recreation and medical care. Originally opened in June for 30 days with a capacity of 400, it expanded in September to be able to house 3,800, and is now expected to remain open at least through the end of the year.
"It is common to use influx shelters as done on military bases in the past, and the intent is to use these temporary facilities only as long as needed," said Ms Evelyn Stauffer, a spokesman for the Health and Human Services Department (HHS).
Ms Stauffer said the need for the tent city reflected serious problems in the immigration system.
"The number of families and unaccompanied alien children apprehended are a symptom of the larger problem, namely a broken immigration system," Ms Stauffer said. "Their ages and the hazardous journey they take make unaccompanied alien children vulnerable to human trafficking, exploitation and abuse. That is why HHS joins the President in calling on Congress to reform this broken system."
But the mass transfers are raising alarm among immigrant advocates, who were already concerned about the lengthy periods of time migrant children are spending in federal custody.
The roughly 100 shelters that have, until now, been the main location for housing detained migrant children are licensed and monitored by state child welfare authorities, who impose requirements on safety and education as well as staff hiring and training.
The tent city in Tornillo, on the other hand, is unregulated, except for guidelines created by the HHS. For example, schooling is not required there, as it is in regular migrant children shelters.
Mr Mark Greenberg, who oversaw the care of migrant children under former president Barack Obama, helped to craft the emergency shelter guidelines. He said the agency tried "to the greatest extent possible" to ensure that conditions in facilities like the one at Tornillo would mirror those in regular shelters, "but there are some ways in which that's difficult or impossible to do".
Several shelter workers, who spoke on condition of anonymity for fear of being fired, described what they said has become standard practice for moving the children: In order to avoid escape attempts, the moves are carried out late at night because children will be less likely to try to run away. For the same reason, children are generally given little advance warning that they will be moved.
At one shelter in the Midwest whose occupants were among those recently transferred to Tornillo, about two dozen children were given just a few hours' notice last week before they were loaded onto buses - any longer than that, according to one of the shelter workers, and the children may panic or try to flee.
The children wore belts with phone numbers for their emergency contacts etched on in pen. One young boy asked the shelter worker if he would be taken care of in Texas. The shelter worker replied that he would, and told him that by moving, he was making space for other children like him who were stuck at the border and needed a place to live.
Some staff members cried when they learnt of the move, the shelter worker said, fearing what was in store for the children who had been in their care. Others tried to protest. But managers explained that tough choices had to be made to deal with the overflowing population.
The system for sheltering migrant children came under strain this summer, when the already large numbers were boosted by more than 2,500 young border crossers who were separated from their parents under the Trump administration's zero-tolerance policy. But those children were only a fraction of the total number who are currently detained.
Most of the detained children crossed the border alone, without their parents. Some crossed illegally; others are seeking asylum.
Children who are deemed "unaccompanied minors", either because they were separated from their parents or crossed the border alone, are held in federal custody until they can be matched with sponsors, usually relatives or family friends, who agree to house them while their immigration cases play out in the courts.
The move to Texas is meant to be temporary. Rather than send new arrivals there, the government is sending children who are likely to be released sooner, and will spend less time there - mainly older children, ages 13 to 17, who are considered close to being placed with sponsors. Still, because sponsorship placements are often protracted, immigrant advocates said there was a possibility that many of the children could be living in the tent city for months.
"Obviously, we have concerns about kids falling through the cracks, not getting sufficient attention if they need attention, not getting the emotional or mental health care that they need," said Ms Leah Chavla, a lawyer with the Women's Refugee Commission, an advocacy group.
"This cannot be the right solution," Ms Chavla said. "We need to focus on making sure that kids can get placed with sponsors and get out of custody."
The number of detained migrant children has spiked even though monthly border crossings have remained relatively unchanged, in part because harsh rhetoric and policies introduced by the Trump administration have made it harder to place children with sponsors.
Traditionally, most sponsors have been unauthorised immigrants themselves, and have feared jeopardising their own ability to remain in the country by stepping forward to claim a child. The risk increased in June, when federal authorities announced that potential sponsors and other adult members of their households would have to submit fingerprints, and that the data would be shared with immigration authorities.
Last week, Mr Matthew Albence, a senior official with Immigration and Customs Enforcement, testified before Congress that the agency had arrested dozens of people who applied to sponsor unaccompanied minors. The agency later confirmed that 70 per cent of those arrested did not have prior criminal records.
"Close to 80 per cent of the individuals that are either sponsors or household members of sponsors are here in the country illegally, and a large chunk of those are criminal aliens. So we are continuing to pursue those individuals," Mr Albence said.
Seeking to process the children more quickly, officials introduced new rules that will require some of them to appear in court within a month of being detained, rather than after 60 days, which was the previous standard, according to shelter workers. Many will appear via video conference call, rather than in person, to plead their case for legal status to an immigration judge. Those who are deemed ineligible for relief will be swiftly deported.
The longer that children remain in custody, the more likely they are to become anxious or depressed, which can lead to violent outbursts or escape attempts, according to shelter workers and reports that have emerged from the system in recent months.
Advocates said those concerns are heightened at a larger facility like Tornillo, where signs that a child is struggling are more likely to be overlooked, because of its size. They added that moving children to the tent city without providing enough time to prepare them emotionally or to say goodbye to friends could compound the trauma that many are already struggling with.