A BBC report said that six others were critically injured in the fire at Hyosarang Hospital, about 300km south of Seoul. The fire was put out within half an hour.
Reportedly, most of the dead were old patients in their 70s and 80s. They died due to suffocation caused by toxic fumes. Most of the victims were unable to escape as their rooms were filled with smoke from the fire.
Reportedly, a nurse died while trying to douse the flames with a fire extinguisher.
The police have arrested an 81-year-old patient suffering from dementia after security video footage showed him entering an area where the fire began, reports said.