By Rich McKay

ATLANTA (Reuters) - A 24-year-old Georgia father, whose twin toddler daughters died after he left them inside a car on a hot and humid day, was arrested early Friday on charges of involuntary manslaughter and reckless conduct, police said.

Police were called Thursday evening to an apartment complex in Carrollton, Georgia, about 50 miles (80 km) west of Atlanta, where the 15-month-old girls Ariel and Alaynah North were found unresponsive after being left for an undetermined amount of time in a car in the parking lot, said police Captain Chris Dobbs.

Weather reports say temperatures in Carrollton reached 90-degrees Fahrenheit (32 Celsius) on Thursday.

“This is just a sad situation,” Dobbs said in a phone interview.“Officers answering a 911 call were motioned to a side yard where the father had the children in an inflatable kiddie pool trying to cool them off. Some neighbors brought ice packs.”

Paramedics rushed the children to the hospital, where they were pronounced dead, Dobbs said. The children's mother was in Atlanta at the time of the incident, local media reported.

The girls' deaths bring the total number of U.S. children who have died this year due to heat stroke in a vehicle to 26, compared to 12 such deaths at this time last year, according to the KidsAndCars.org advocacy group.

The father, Asa North, was charged with two counts of involuntary manslaughter and two counts of reckless conduct. No bond or lawyer information was available Friday morning.

“We believe he left the children in the car, but we’re not getting into what his story is at this time,” Dobbs said.

A medical examiner with the Georgia Bureau of Investigation in Atlanta is scheduled to conduct autopsies on Friday to determine the official cause of death and possibly how long the children were left in the heat, he said.

(Editing by Colleen Jenkins and Bernadette Baum)