SAN ANTONIO DE CORTEZ, Guatemala - The 7-year-old Guatemalan migrant girl who died after being detained by US border agents this month was inseparable from her father and had looked forward to being able to send money home to support her impoverished family, relatives said on Saturday.

Nery Caal, 29, and his daughter Jakelin were in a group of more than 160 migrants who handed themselves in to US border agents in New Mexico on Dec. 6. Jakelin developed a high fever while in the custody of US Customs and Border Protection and died two days later at a hospital in El Paso, Texas.

"The girl said when she was grown up she was going to work and send dough back to her mom and grandma," said her mother Claudia Maquin, who has three remaining children, speaking in the Mayan language Q'eqchi and betraying little outward emotion.

"Because she'd never seen a big country, she was really happy that she was going to go," she added, explaining how her husband had gone to the United States to find a way out of the "extreme poverty" that dictated their lives.

Corn stood behind her palm-thatched wooden house and a few chickens and pigs scrabbled in the yard as she spoke, dressed in a traditional blouse with a 6-month-old baby in her arms.

A family photograph at the house showed Jakelin smiling and looking up at the camera, wearing a pink T-shirt with characters from the cartoon series "Masha and the Bear."

Deforestation to make way for palm-oil plantations has made subsistence farming increasingly hard for the 40,000 inhabitants of Raxruha municipality, where the family's agricultural hamlet of San Antonio de Cortez lies in central Guatemala, local officials said. That has spurred an exodus of migrants.

Setting out on Dec. 1, Caal and his daughter travelled more than 2,000 miles (3,220 km) so Jakelin's father could look for work in the United States, said her mother, who learned of the girl's death from consular officials.

Almost 80 per cent of Guatemala's indigenous population are poor, with half of those living in extreme poverty. The mayor of San Antonio de Cortez described the Caal family as among the worst off in the village.

Mayor Cesar Castro said in recent months more and more families were uprooting to try to reach the United States, often selling what little land they owned to pay people traffickers thousands of dollars for the trip.

"It's not just the Caal family. There are endless people who are leaving," Castro said. "I see them drive past in pickups, cars and buses." He said most of them came back in the end, often penniless after being dropped off by traffickers, caught by authorities and deported.

Jakelin's death has added to criticism of US of President Donald Trump's hard-line immigration policies from migrant advocates and Democrats in the US Congress.

The US government defended Jakelin's treatment, and said there was no indication she had any medical problems until several hours after she and her father were taken into custody.

The father, speaking through a representative in Texas, agreed with that account, saying the girl exhibited no sign of distress at the border. The family, in a statement issued by their attorneys in El Paso, disputed as erroneous media reports that the girl had gone for days without food or water or became severely dehydrated.

INSEPARABLE

Domingo Caal, Jakelin's grandfather, said she had gone on the journey because she did not want to leave her father.

"The girl really stuck to him. It was very difficult to separate them," said Domingo, 61, wearing muddy boots and a faded and torn blue shirt.

Jakelin's uncle, Jose Manuel Caal, said he had heard she was ill before she died, but had expected her to recover. "The girl's death left us in shock," he said.

The family hope the girl's father can remain in the United States.

"What I want now is for Nery to stay and work in the United States. That's what I want," said his wife.

A Guatemalan consular official told Reuters on Friday that Caal told him he had crossed the border planning to turn himself in to US authorities, and will try to stay.

Record numbers of parents travelling with children are being apprehended trying to cross the US border with Mexico. In November, US Customs and Border Protection (CBP) officers detained 25,172 members of "family units," the highest monthly number ever recorded, the agency said.

Parents with children are more likely to be released by US authorities while their cases are processed because of legal restrictions on keeping children in detention.

Caal remains in the El Paso area, where his daughter died after being flown by helicopter to a hospital there for emergency treatment when she stopped breathing.

A brain scan revealed swelling and Jakelin was diagnosed with liver failure. She died early in the morning on Dec. 8, with her father at the hospital, a CBP official said.

US authorities are investigating the death.