SEOULgameseum, June 24 (Xinhua) -- One person was killed in South Korea's battery plant fire on Monday and more casualties were feared as 21 people were believed to be trapped inside, according to Yonhap news agency.

The fire broke out at a primary battery plant in Hwaseong, around 45 km south of the capital Seoul, at about 10:31 a.m. local time (0131 GMT).

One person died after having been found in cardiac arrest. Another was seriously injured, while two others suffered minor injuries such as smoke inhalation.

Of the combined 67 workers, 21 failed to be reached and were believed to be trapped inside the plant, raising fears of more casualties.

Some 35,000 lithium batteries were estimated to be stored on the second floor of the three-story reinforced concrete factory with a total floor area of 2,300 square meters or so.

The fire authorities mobilized 159 firefighters and 63 pieces of equipment, but they struggled to extinguish the fire because of the difficulty in putting out the flame of lithium batteries.

Rescue workers had yet to go inside and search for the possible victims due to the continued explosion of the batteries.■