Authorities say an intense, fast-moving fire has destroyed four connected homes in Perth Amboy, N.J., and seriously injured three people, including an infant.

Forty-seven people were left homeless by the five-alarm blaze, which was reported around 3:45 a.m. Sunday. Two residents -- a father and son -- initially were unaccounted for, but authorities later learned they weren't home when the fire occurred.

A couple and their baby daughter suffered burns. They are hospitalized in serious but stable condition.

Roughly 75 firefighters battled the stubborn blaze, which damaged several other homes and burned for several hours before it was brought under control.

The cause of the fire remains under investigation. Witnesses say it appeared to be "raining ashes" as crews worked to extinguish the flames.