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.

While the extent of the damage has yet to be determined, it is expected to take some time before the plant can resume normal operations. (Yonhap)