About 20 bodies were found at the site of a lithium battery plant fire in Hwaseong, south of Seoul, on Monday.
Local authorities announced earlier that one worker was killed and three others were injured in the blaze.
According to firefighters, the bodies found at the site are believed to be among 23 people unaccounted for in the fire, amid fears the death toll could rise further.
The fire reportedly occurred for unknown reasons at the three-story, reinforced concrete building with a total floor space of about 2,300 square meters, according to Yonhap News Agency.
Firefighters reportedly had difficulties completely putting out the blaze because burning lithium batteries are difficult to handle by conventional fire extinguishing methods.
