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.

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

“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.

The cause of the fire remains under investigation.