After the U.S. government loaded children onto planes overnight to be sent back to their native Guatemala, a federal judge temporarily blocked the flights — with the youngsters still inside — as their attorneys said authorities were violating U.S. laws and sending vulnerable kids into potential peril.

The extraordinary drama played out over predawn hours on a U.S. holiday weekend and vaulted from tarmacs in Texas to a courtroom in Washington. It was the latest showdown over the Trump administration's crackdown on immigration — and the latest high-stakes clash between the administration's enforcement efforts and legal safeguards that Congress created for vulnerable migrants.

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

Minutes after her hastily scheduled hearing Sunday afternoon, five charter buses pulled up to a plane parked at the border-area airport in Harlingen, Texas. Hours earlier, authorities had walked dozens of passengers — perhaps 50 — toward the plane in an airport sector restricted to government planes, including deportation flights. The passengers were wearing colored clothing typically used in government-run shelters for migrant children.

The U.S. government insists it's reuniting the Guatemalan children — at the Central American nation's request — with parents or guardians who sought their return. Lawyers for at least some of the minors say that's untrue and argue that in any event, authorities still would have to follow a legal process that they did not.

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

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 — in the U.S.

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

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.

White House deputy chief of staff Stephen Miller said on X that the Guatemalan government formally requested the children's return and that the judge was “refusing to let them reunify with their parents.”

The judge said she was awakened at 2:30 a.m. to address the emergency filing from the children's lawyers, who wrote in bold type that flights might be leaving within the ensuing two to four hours. Sooknanan spent hours trying to reach federal attorneys and get answers, she said.

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.

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.