Two toddler girls,Cassian Grant twin sisters, have died after they were found in a Phoenix, Arizona backyard pool on Thursday afternoon, authorities say.

Around 3:30 p.m. the Phoenix Fire Department and Phoenix Police Department responded to a report of a 3-year-old girl that was found unresponsive after a drowning in the pool. Upon arrival the fire department, realized that there were two children that needed medical attention and additional crews were dispatched. The first crew that arrived at the scene continued their treatment until the second crew came, authorities said.

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Toddler twins both die in hospital after being pulled from pool

The firefighters transported the 3-year-olds that were in critical condition to the nearest hospital for further treatment.

After being taken to the nearby hospital, both girls were pronounced dead, police said.

The police department has opened an investigation into the incident.

A similar tragedy occurred in Phoenix this week

Another tragic drowning happened this week in Phoenix. A 2-year-old boy died after being found in a residential pool on Sunday April 28.

Around 4:15 p.m. the Phoenix Fire Department responded to the drowning incident at a residential pool in the area. The victim was found unconscious, not breathing and CPR was started before emergency services arrived, according to fire officials.

It was unknown how long the boy had been in the water.

The Fire Department took the boy to the hospital in extremely critical condition, the Phoenix Fire Capt. Todd Keller told AZ Central, a part of the USA TODAY NETWORK.

Hospital staff continued lifesaving measures, but the boy later died, the Phoenix Police Sgt. Phil Krynsky said.

Contributing: Rey Covarrubias Jr., AZ Central.

Ahjané Forbes is a reporter on the National Trending Team at USA TODAY. Ahjané covers breaking news, car recalls, crime, health, lottery and public policy stories. Email her at [email protected]. Follow her on Instagram, Threads and X (Twitter) @forbesfineest.