UNION CITY -- A family of six was displaced and their dog killed after an early-morning fire tore through their Union City home Wednesday, authorities said.

About 12:30 a.m., firefighters responded to the one-alarm fire on the 33500 block of Sixth Street, Alameda County fire Batallion chief Kris Kerstetter said.

The fire started in the back of the one-story house, fully engulfing two bedrooms, the kitchen, an enclosed patio and a carport in flames, Kerstetter said. The fire was contained within 20 minutes.

None of the residents were injured in the blaze, though a small dog was killed, Kerstetter said. The four adults and two children were displaced from the home, and will receive assistance with temporary housing from the American Red Cross.

Damage to the home was estimated at about $100,000, Kerstetter said. The cause of the fire is under investigation.

Contact Erin Ivie at 925-845-2122. Follow her at Twitter.com/erin_ivie.