OKLAHOMA CITY (KFOR) — Two 18-month-old children are dead after drowning in a backyard swimming pool Thursday morning at a home in northwest Oklahoma City.

When firefighters pulled up to the home in the Cobblestone neighborhood, they found the children had already been pulled out of the water by a parent who was administering CPR. 

First responders continued CPR on the children as they transported them to Baptist Hospital.  

“It was a male and female… They were siblings,” said Greg Merrell, Battalion Chief OKCFD. 

They were two twins, according to several neighbors.

The Oklahoma City Fire Department told NewsNation affiliate KFOR they are not sure how long the kids were in the pool. 

“I saw the mother who was distraught, who got in an EMS vehicle,” said neighbor Mike Bernard. 

Neighbors watched and prayed as first responders attempted to save the twins’ lives. 

“They brought out two little children and put them in separate ambulances. And they were doing CPR on both little children,” said Bernard.  

Unfortunately, despite the efforts of family and first responders, the children were later pronounced dead.

Bernard said the family moved into this home about a year ago. 

Other neighbors told KFOR there were six total children who lived in the home with two parents and one grandmother.  

Oklahoma City Police are investigating and say the incident does not appear to be criminal in nature at this time.