A photo shared by a reader shows a fire at the POSCO steel factory in Pohang, North Gyeongsang Province, Nov. 10. Yonhap

A fire broke at a POSCO factory in the southeastern city of Pohang early Sunday, leaving one worker injured, fire authorities said.

The fire started with multiple explosions at the steel company's third Finex furnace of the plant, located about 270 kilometers southeast of Seoul, at around 4:20 a.m. The blaze was initially contained by around 6:30 a.m. and completely extinguished at around 9:20 a.m.

Witnesses reported hearing explosions that felt like an earthquake, and some said they felt the ground tremble.

Fire authorities initiated an emergency response at around 4:50 a.m., deploying 43 fire trucks and about 120 firefighters. The 50-meter-high facility made firefighting efforts challenging, according to the authorities.

One POSCO worker inside the plant suffered burn injuries, while seven others evacuated safely. Authorities are currently investigating the case of the fire and assessing the extent of the damage.

The third Finex furnace, where the fire occurred, was completed in 2014. It is said to be capable of producing around 2 million tons of molten iron annually, accounting for approximately 10 percent of the total production at POSCO's Pohang plant.

The company said its production would not be disrupted by Sunday's fire, as it also operates a larger steel plant in Gwangyang, about 290 kilometers south of Seoul.

While the extent of the damage has yet to be determined, industry experts estimated it would take at least a week before normal operations at the Pohang plant can resume. (Yonhap)

A photo shared by a reader shows a fire at the POSCO steel factory in Pohang, North Gyeongsang Province, Nov. 10. Yonhap