A fire destroyed a duplex Thursday morning south of West Main Street, displacing two families.

The blaze at 118 Mechanic St., a house split into two apartments, was reported about 8:30 a.m., the Fort Wayne Fire Department said.

When fire crews arrived, flames on the first floor had spread throughout the house. No one was inside at the time.

Crews entered the house to extinguish the flames and brought the fire under control in 1 hour, 23 minutes, the department said.

Investigators blamed the fire on “improperly discarded smoking materials,” the department said.

The American Red Cross came to the scene to help the residents of the duplex. One of them reported that two cats were missing.