HARLINGEN, Texas (AP) — In a dramatic turn of events, just as U.S. officials were about to send a group of children back to Guatemala on overnight flights, a federal judge halted the action while the children were still onboard. Attorneys argued that the authorities were flouting U.S. laws and potentially putting the vulnerable youths in danger.

This intense situation unfolded during the early hours of a holiday weekend, stretching from Texas airstrips to a courtroom in Washington D.C. It marked the latest escalation in the Trump administration’s stringent immigration enforcement, pitting its actions against the legal protections intended for at-risk migrants that Congress has established.

For now, hundreds of Guatemalan children who arrived unaccompanied will stay while the legal fight plays out over coming weeks.

“Let there be no confusion,” said Judge Sparkle L. Sooknanan, emphasizing that her decision extends to Guatemalan minors who enter the U.S. unaccompanied by parents or guardians.

Shortly after a quickly arranged hearing concluded on Sunday afternoon, five charter buses arrived at an aircraft in Harlingen, Texas. Earlier that day, officials had guided numerous passengers — possibly around 50 — toward a section of the airport dedicated to government operations, such as deportation flights. The group was dressed in colored attire typical of those in government-run shelters for migrant children.

The U.S. government maintains that these actions are part of reuniting the Guatemalan children with their families or guardians who have requested them back. However, the minors’ attorneys call this claim questionable, stressing that any such reunification should still adhere to established legal procedures, which they argue had not been followed.

One of the lawyers, Efrén C. Olivares from the National Immigration Law Center, recounted how a girl’s parents in Guatemala received an unexpected call saying she was being deported. Some children—identified only by initials in legal documents—described being neglected, abandoned, or suffering threats and abuse in their home country.

Sunday’s court hearing came in a case filed in federal court in Washington, but similar legal actions also were filed elsewhere.

In a lawsuit in Arizona, the Florence Immigrant & Refugee Rights Project said one of its clients is a 12-year-old asylum-seeker who has chronic kidney disease, needs dialysis to stay alive and will need a kidney transplant. Two other plaintiffs, a 10-year-old boy and his 3-year-old sister, don’t have family in Guatemala and don’t want to return, according to the group.

Families scramble to Guatemalan air base

As the developments played out in the U.S., families gathered at an air base in Guatemala’s capital, Guatemala City, in anticipation of the flights. Gilberto López said he drove through the night from his remote town after his 17-year-old nephew called at midnight, saying that he was being deported from Texas.

The boy left Guatemala two years ago, at age 15, to work in the U.S. and was detained about a month ago, López said.

Alarm bells for immigrant advocates

Migrant children who arrive in the U.S. without their parents or guardians are routinely handed over to the Department of Health and Human Services’ Office of Refugee Resettlement. They often live in government-supervised shelters or with foster care families until they can be released to a sponsor — usually a relative — living in the country.

Many of those from Guatemala request asylum or pursue other legal avenues to get permission to stay the U.S.

An attorney with the National Center for Youth Law said the organization starting hearing a few weeks ago from legal service providers that Homeland Security Investigations agents were interviewing children — particularly Guatemalans — in facilities of the Office of Refugee Resettlement.

The agents asked the children about their relatives in Guatemala, said the attorney, Becky Wolozin.

Then, on Friday, advocates began getting word that their young clients’ immigration court hearings were being canceled, Wolozin said.

Shaina Aber of Acacia Center for Justice, an immigrant legal defense group, said it was notified Saturday evening that officials had drafted a list of children to return to Guatemala. Advocates learned that the flights would leave from the Texas cities of Harlingen and El Paso, Aber said.

It’s unclear whether any planes actually departed. Government lawyer Drew Ensign told the Washington judge that one plane might have taken off but then returned.

The Department of Homeland Security, Immigration and Customs Enforcement and HHS did not immediately respond to requests for comment Sunday.

The judge said that after being awakened at 2:30 a.m. to address the emergency filing from the children’s lawyers, she spent hours trying to reach federal attorneys and get answers.

“I have the government attempting to remove unaccompanied minors from the country in the wee hours of the morning on a holiday weekend, which is surprising,” Sooknanan said at the hearing, later adding: “Absent action by the courts, all of those children would have been returned to Guatemala, potentially to very dangerous situations.”

The rapid-fire developments resembled a March weekend showdown over the deportation of hundreds of Venezuelans to a maximum-security prison in El Salvador. Advocates implored a federal judge to halt deportations they believed were imminent, while the Trump administration was mum about its plans.

That judge appeared in civilian clothes for a Saturday night hearing and tried to block the flights, but they went ahead, with the government saying the order came too late.

Trump administration plans to remove nearly 700 Guatemalan children

The Trump administration is planning to remove nearly 700 Guatemalan children who came to the U.S. unaccompanied, according to a letter sent Friday by Sen. Ron Wyden, an Oregon Democrat. The Guatemalan government has said it’s ready to take them in.

It is another step in the Trump administration’s sweeping immigration enforcement efforts, which include plans to send a surge of officers to Chicago for an immigration crackdown, ramping up deportations and ending protections for people who have had permission to live and work in the United States.