HILLSBORO, Ore. - A fire at Mooberry Elementary School in the wee hours of Friday morning in its kindergarten building has left one of its two class rooms charred beyond recognition. 

The school's alarm system notified the nearest station, Hillsboro Fire and Rescue, at the start of the fire. Hillsboro Fire and Rescue's engine company No. 1 arrived to respond the alarm at 3:58 a.m. Crews found flames venting from the southwest corner of the kindergarten building's roof and the glass entry door on the building's west side. Three additional engine companies and one truck company were called in for support, including an engine from Washington County Fire District 2.

The kindergarten building, at 1230 N.E. 10th Ave. in Hillsboro, is a freestanding stucture of roughly 1,600 square feet. Hillsboro Fire and Rescue reports no fire or smoke damage to any other areas of the school. Classes are out for summer. Sept. 8 is the first day of school for Mooberry students; Sept.10 is the first day for kindergarten.

"When kindergarten starts next fall, they have classrooms inside the main building where they can meet," said Hillsboro Fire and Rescue spokesperson Bruce Montgomery.

Firefighters entered the building through the glass door and found fire and heavy smoke throughout the southwest side of the building. Firefighters were able to contain the fire in the classroom where it started, though there is extensive smoke and heat damage to the entire building.

Mooberry Elementary School officials are in the process of estimating the cost of the damage to the building and its contents. This comes at a time when the school is already undergoing a re-roofing project.

Cause of the fire is under investigation by Hillsboro Fire and Rescue. Reports give no indication that the school's re-roofing project had anything to do with the fire.

"Sometimes it is obvious," said Montgomery of the fire's origin. "...With this one it's definitely not a slam dunk. Our investigators have been in there for quite a while and they're in the process of trying to figure out how this started."

- Hillsboro Fire and Rescue contributed to this report.