BROOKLYN, N.Y. — Fire officials in Brooklyn are investigating the cause of a four-alarm fire that broke out early Friday morning inside a residential building.

FDNY crews responded to the call around 6:30 a.m. inside 132 Montague Street in Brooklyn Heights.

Fire officials say it began on the third floor and spread to the fourth and fifth floors.

The FDNY says three firefighters suffered burns and a fourth was treated for a neck injury.

All of the injuries are described as non-life-threatening.

The FDNY says many of those living in the building were not home at the time of the fire.

At least one resident was displaced and is being helped by the Red Cross.