A teenage girl and her younger brother were killed after a devastating fire tore through their family home in Westchester County, trapping them inside as firefighters rushed to rescue them.

The deadly three-alarm blaze broke out around 2:30 a.m. Wednesday at a home in Cortlandt Manor.

The teens’ mother, who managed to escape, frantically informed firefighters that her children were trapped in their second-floor bedrooms as flames roared from doors and windows.

Fire crews quickly deployed ground ladders, smashed through windows, and pulled the siblings — 17-year-old Alina Toone and 15-year-old Jeremiah Toone — from the 1,850-square-foot burning home while battling the intense inferno.

“Crews began an impeccable strategy called vent-enter-isolate-search. We couldn’t get enough access through traditional means, so crews had to get these patients out of the windows above grade,” Mohegan Lake Fire Chief Thomas Eade told News 12.

“The initial couple of minutes, we had two members in each window, and two members trying to attack the fire once the patients were brought out in serious condition.”

Eade said both teenagers suffered horrific burns over more than 50% of their bodies and were in cardiac arrest when they were pulled from the Sherwood Road residence. Medics performed CPR at the scene and successfully restored their pulses.

Alina Toone was transported to Westchester Medical Center in Valhalla, where she was pronounced dead. Jeremiah Toone was taken to NewYork-Presbyterian Hudson Valley Hospital, where he also died later that Wednesday.

Their mother and older brother, who had been sleeping downstairs, escaped the home before firefighters arrived. One firefighter was hospitalized for exhaustion.

Westchester County officials confirmed that the teens’ father, Gregory Toone, is a county correction officer. It remains unclear whether he was home at the time of the fire.

“Our hearts are with Officer Toone, his family, loved ones and everyone grieving this unimaginable loss. We are also praying for the recovery of the surviving victims and for strength for the entire family in the difficult days ahead,” Westchester County Executive Ken Jenkins said in a statement.

More than 45 firefighters responded to the scene. The fire has been ruled accidental and was caused by an electrical issue involving a power strip.