Citizen app video shows where the smoke and flames broke out just before 4 a.m. on the first floor of a 7-story building on Homecrest Avenue in the Sheepshead Bay section.
More than 100 firefighters were brought to the scene and were able to bring it under control just after 5 a.m.
Twelve residents and three firefighters were injured, all considered to be minor.
The firefighters were taken to the hospital for treatment.
The cause of the fire is under investigation.
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