Authorities said a fire that heavily damaged a house in Clairemont Sunday, but didn't injure anyone, and was caused by some sort of unspecified accident.

The blaze was reported around 8:40 a.m. in an attic of the house at 5605 Birkdale Way, in a neighborhood just south of Madison High School, a San Diego Fire-Rescue dispatcher said.

Firefighters saw flames and smoke as they arrived at the house and soon after reported the structure was fully involved, according to the dispatcher.

It took about a half-hour to extinguish the flames, and two residents were displaced.

The dispatcher said damage was estimated at $100,000 to the structure and $40,000 for contents.