A young girl has died after being taken into custody at the US-Mexico border.

The seven-year-old, originally from Guatemala, is said to have crossed the border illegally with her father.

They were among more than 160 people who handed themselves into border patrol officers last Thursday, December 6th.

According to The Washington Post, the young girl died of dehydration and shock around eight hours after she was taken into custody near the city of Lordsburg in New Mexico.

The paper quotes US Customs and Border Protection as saying the girl "reportedly had not eaten or consumed water for several days".

After having seizures, the child was flown to a hospital by helicopter.

However, she went into cardiac arrest - and, despite being revived by medics, she died less than 24 hours after being taken into custody.

In a statement quoted by CNN, the US Department of Homeland Security said officials took "every possible step to save the child's life under the most trying of circumstances".

Authorities expressed their sympathies to the family of the girl.

An investigation is now underway to ensure "all appropriate policies were followed".

The incident comes amid increased security at the US southern border, as well as increased criticism from civil rights groups of the treatment of migrants and refugees entering the US.

The ACLU Border Rights Centre said: "This tragedy represents the worst possible outcome when children are held in inhumane conditions.

"We call for a rigorous investigation into how this tragedy happened and serious reforms to prevent future deaths."