A 7-year-old girl who crossed the U.S.-Mexico border with her father last week died after being taken into the custody of the U.S. Border Patrol, federal immigration authorities confirmed Thursday.

The Washington Post reported the girl died of dehydration and shock more than eight hours after she was arrested by agents near Lordsburg, New Mexico. The girl was from Guatemala and was traveling with a group of 163 people who approached agents to turn themselves in on Dec. 6.

It's unknown what happened to the girl during the eight hours before she started having seizures and was flown to an El Paso hospital.

In a statement, Customs and Border Protection said the girl had not eaten or consumed water in several days. The agency did not provide The Associated Press with the statement it gave to the Post, despite repeated requests.

The Department of Homeland Security, in a Thursday night statement, expressed its "sincerest condolences" to the family of the child and said Border Patrol agents "took every possible step to save the child's life under the most trying of circumstances."

“As we have always said, traveling north illegally is extremely dangerous. Drug cartels, human smugglers and the elements pose deadly risks to anyone who comes across the border illegally," the statement reads. "Border Patrol always takes care of individuals in their custody and does everything in their power to keep them safe. Every year the Border Patrol saves hundreds of people who are overcome by the elements between our ports of entry.

"Unfortunately, despite our best efforts and the best efforts of the medical team treating the child, we were unable to stop this tragedy from occurring," the statement continues. "Once again, we are begging parents to not put themselves or their children at risk attempting to enter illegally. Please present yourselves at a port of entry and seek to enter legally and safely.

The girl's death raises questions about whether border agents knew she was ill and whether she was fed anything or given anything to drink during the eight-plus hours she was in custody.

Immigrants, attorneys and activists have long raised issues with the conditions of Border Patrol holding cells. In Tucson, an ongoing lawsuit claims holding cells are filthy, extremely cold and lacking basic necessities such as blankets. A judge overseeing that lawsuit has ordered the agency's Tucson Sector, which patrols much of the Arizona-Mexico border, to provide blankets and mats to sleep on and to continually turn over surveillance footage from inside the cells.

The death of the 7-year-old comes after a toddler died in May just after being released from an ICE family detention facility in Texas, and as the administration of Donald Trump attempts to ban people from asking for asylum if they crossed the border illegally. A federal appeals court has temporarily blocked that ban, but the administration asked the U.S. Supreme Court to reinstate it Tuesday.

Cynthia Pompa, advocacy manager for the ACLU Border Rights Center, said migrant deaths increased last year even as the number of border crossing dropped.

"This tragedy represents the worst possible outcome when people, including children, are held in inhumane conditions. Lack of accountability, and a culture of cruelty within CBP have exacerbated policies that lead to migrant deaths," Pompa said. (AP)

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