South Korean fire department officials said Tuesday that three teenage boys were presumed dead and seven other boys were being treated for injuries after they were found unconscious at a motel in the seaside town of Gangneung.

An official from Gangwon Fire Headquarters said the cause of the injuries was unclear although gas leakage was a possibility. He said there were no immediate signs indicating suicide attempts or foul play. The official didn't want to be named, citing office rules.