The cause of an apartment fire in the Bronx that killed at least 12 people was started by a child who was playing with a stove, Fire Commissioner Daniel Nigro says. 

The fire broke out Thursday around 7 p.m. inside a Prospect Avenue apartment building near the Bronx Zoo.

According to Nigro, the fire was sparked by a 3-and a half-year-old boy who was playing with stove burners. 

The fire began inside the kitchen on the first floor of a five-story building and quickly spread.

Nigro says the boy’s mother was not in the kitchen when the fire started, however, she and her two children ran out of the apartment and left their door open once they realized the fire was out of control.

During a press conference Friday, Nigro explained it was because the door was left open which allowed the fire to spread quickly through the corridor of the building, trapping and killing five people in a very short period of time. 

Among the dead are a 1-year-old girl and 63-year-old woman. Seven others died at Saint Barnabas Hospital and Jacobi Medical Center as a result of their injuries, officials say. At least 12 people escaped the fire by climbing down fire escapes and FDNY rescue ladders. 

Two people remain in critical condition at Jacobi Medical Center, and one is in serious condition. Other residents of the building are still missing or unaccounted for, according to officials.

At least 175 firefighters responded to the initial call in 3 minutes, and the fire was extinguished hours later. 

Nigro described the fire as "historic in its magnitude" due to the high death toll.

The mayor called the fire one of the most tragic in recent New York City history.

The American Red Cross is helping victims of the fire. A shelter has been set up at Crotona International High School near the apartment building where the fire took place.

Anyone who has relatives or friends who live in the apartment and have not heard from them are asked to call 311.

Nigro reminded the public of programs designed to educate young children about the dangers of fire. 

He says it is not uncommon for children to play with fire, and that the mother of the 3-year-old boy accused of starting the fire told police the boy had a history of playing with the stove burners.

City officials say they are hosting a coat and clothing collection drive for the victims at the Church of St. Martin of Tours Saturday and Sunday from 9 a.m. to 4 p.m. It is located at 2239 Crotona Ave.

State Assemblyman Luis Sepulveda and the Parkchester Baptist Church are also offering food and clothing to the victims. They can call 347-270-5044 or the church directly at 718-823-8124, Sepulveda says.