Enumclaw Middle School was evacuated this morning after a phone exploded in the school court.

Students left the building at about 9 a.m.; Enumclaw School District officials said they expected kids to return inside by 10 a.m.

An initial Facebook post from the district said “a small explosive device” detonated, and confirmed about half an hour later that it was a phone.

“Upon investigation, law enforcement confirmed the source was a cell phone battery that had caught fire after being thrown to the ground. The fire was quickly extinguished by staff, and no injuries have been reported,” ESD posted. “… We are proud of the swift response by our students and staff, and we are deeply grateful to the Enumclaw Police Department, Washington State Patrol, and Enumclaw Fire Department for their immediate response and support.”