(Reuters) - Reports of an “active shooter” situation at a North Carolina high school on Friday was a false alarm caused by a faulty water heater that sounded like machine gun fire, local media reported.

“There’s no active shooter,” the Fayetteville Observer quoted Pender County, North Carolina, emergency management director Tom Collins as saying. “It’s a malfunctioning water heater.”

Collins said a popping sound from the heater “sounded just like an AR-15 (semiautomatic rifle) going off,” the newspaper reported. It prompted evacuations and lockdowns at Topsail High School in the unincorporated town of Hampstead

Collins did not immediately respond to a request for comment on Friday.

It was not immediately clear what caused the water heater to malfunction.