The fire broke out at 17 Heritage Dr. just after 12:30 p.m.
The structure was fully engulfed in flames when emergency responders arrived a short time later. No one was injured and the New City Fire Department and seven surrounding departments were able to extinguish the fire, Clarkstown Police said.
Three units of the complex were damaged and considered uninhabitable.
The three impacted families will be staying with relatives or going to hotels due to the state of the structure.
The Clarkstown Detective Bureau and the Clarkstown Fire Inspector are on scene to investigate the fire. At this point, there is no reason to suspect the fire was suspicious, police said.
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