SEA ISLE CITY, N.J. (CBS) – An early morning fire tore through three houses on Friday in Sea Isle City

It happened around 5:30 a.m. near 91st Street and Pleasure Ave.

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Fire officials tell CBS3 that the blaze spread to three homes which authorities believe to be unoccupied.

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“There was extensive damage to three total structures, one single family and two duplex dwellings,” said a spokesperson for the city.

A fireman on the scene received treatment for a minor injury.

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The cause of the fire remains under investigation.