SEOUL - A total of 16 people died after a fire broke out at a South Korean battery plant on Monday, and 21 people remained missing, a fire official told a briefing. 

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

Firefighters went inside the factory and searched the possible victims after extinguishing a large blaze at about 3:10 pm local time (0310 GMT).

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.

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.

Before the internal search operation, one person died after having been found in cardiac arrest.

Two others were seriously wounded, while four suffered minor injuries such as smoke inhalation.