More than 1,600 migrant children in U.S. custody have quietly been relocated in recent weeks from private foster homes and shelters to a barren tent city in the Texas desert, The New York Times reported on Sunday.

Most of the children were moved “under the cover of darkness” and with almost no prior warning, according to the paper. They were roused from sleep in the middle of the night so they would be “less likely to try to run away” and loaded onto buses bound for the sprawling tent city in Tornillo, a border town in El Paso County.

The relocation is part of what the report called a mass reshuffling by the Trump administration, burdened by caring for 12,800 undocumented migrant children ― a record number ― now in federal custody.

Every week, hundreds of children — mostly aged 13 to 17 — are being moved from foster homes and shelters across the country to the tent city, which provides no formal schooling and limits access to legal services, the Times reported.

MSNBC correspondent Jacob Soboroff reported there were more than 1,300 migrant children in the tent city at the end of September.

“That’s almost as many people as the nearby town of Tornillo itself,” Soboroff noted.

The Department of Health and Human Services said recently it was more than tripling the size of the tent city to nearly 4,000 beds and would keep the temporary camp open at least through the end of the year.

A surge of undocumented children at the border ― and not the Trump administration’s zero-tolerance policy of separating migrant families ― was driving the need for more beds, HHS spokesman Kenneth Wolfe told The Washington Post last month. Officials have “worked round the clock to add beds or add shelters to avoid any backup” at the border, Wolfe said.

A follow-up New York Times article reported that huge increases in the number of detained migrant children in recent months were due to a reduction in the number being released by the federal government to live with families and other sponsors ― and not an influx at the border.