Bronx apartment fire kills 1-year-old, pair of 6-year-olds in critical condition

A 1-year-old boy was killed and a pair of 6-year-olds are in critical condition after being injured in an apartment fire in the Bronx on Monday afternoon.

Here's what we know

Police responded to a 911 call for a fire on the second floor at 2609 Bainbridge Ave., between East 193rd and 194th streets, in the Fordham section at around 3:40 p.m.

EMS arrived on the scene not long after and transported the three children -- two boys and a girl -- who had suffered smoke inhalation to St. Barnabas Hospital, where the 1-year-old was pronounced dead.

Five other people were injured, fire officials said.

The FDNY said 21 units made up of 80 firefighters and EMS personnel responded to the fire, and at least 10 residents of the building were displaced.

The cause of the fire is being investigated.

Fire may have spread through open doors, FDNY says

It is believed that the fire was exacerbated by residents in the building leaving doors open, which the FDNY has been telling the public not to do, in the wake of deadly fires over the last few weeks in the Inwood section of Manhattan and the Belmont section of the Bronx.

"The fire rapidly extended up the stairs, through the bulkhead, the staircase on the top of the building, forcing people to the windows and other civilians to look for ways out," said Malcolm Moore, FDNY assistant chief of special operations. "We've had several of these fire lately where the occupants of the fire apartment have fled the building and left the apartment door open. That appears to be the case here again."

Please stay with CBS News New York for more on this developing story.