The girl and her mother were among a group of Indians dropped off by smugglers in a remote border area.

A six-year-old migrant child from India died of heat stroke after her mother left her with other migrants to go in search of water, a medical examiner and U.S. Border Patrol said on Friday.

The girl, Gurupreet Kaur, who was soon to celebrate her seventh birthday, was found on Wednesday by U.S. Border Patrol west of Lukeville, Arizona, where temperatures reached a high of 108 degrees Fahrenheit (42 Celsius), U.S. Border Patrol and the Pima County Office of the Medical Examiner (PCOME) said.

The girl's death, the second recorded fatality of a migrant child this year in Arizona's southern deserts, highlighted the danger of summer heat as a surge of migrant families, mainly from Central America cross the U.S.-Mexico border to seek asylum.

An increasing number of Indian nationals are crossing into the United States from Mexico, according to immigration officials. They are among thousands of Africans and Asian migrants who fly to third countries and then embark on an arduous trek through Mexico and into the U.S. southern deserts led by smuggling cartels.

The girl and her mother were among a group of five Indian nationals dropped off by smugglers in a remote border area at 10 a.m. on Tuesday, 17 miles (27 km) west of Lukeville, a U.S. border town 50 miles (80 km) southwest of Tucson.

After walking some way, the girl's mother and another woman went in search of water, leaving her daughter with another woman and her child.

"Once they went to look for water they never saw them again," said U.S. Border Patrol Agent Jesus Vasavilbaso.

The mother and the other woman wandered in the desert and were found at 8 a.m. on Wednesday morning, 22 hours after their drop off, by a Border Patrol agent who tracked their footprints.

The mother, who did not speak English, communicated through sign language that she had left behind her daughter and two others, prompting a search by U.S. and Mexican authorities, Vasavilbaso said.

Four hours later, Border Patrol agents found the body of the deceased girl a mile (1.6 km) from the border.

Border Patrol blamed the death on the smugglers for abandoning women and children in the Sonoran desert wilderness.

"This is a senseless death driven by cartels who are profiting from putting lives at risk," Tucson Chief Patrol Agent Roy Villareal said in a statement.

Agents tracked the remaining woman and her 8-year-old daughter's footprints into Mexico. The mother and child re-entered the United States around midnight on Wednesday and surrendered to Border Patrol.

The deceased girl died of hyperthermia and her death was ruled an accident, said Greg Hess, PCOME Chief Medical Officer.

Up to May 30 of this year, PCOME recorded 58 migrants deaths in southern Arizona, most heat related. It recorded 127 deaths in 2018.