A fire broke out at the COEX mall in southern Seoul on Friday morning. 

Fire officials said they received a report at 11:06 a.m alerting them that a fire started in a restaurant on the second floor of the center. 

Fire authorities brought the fire under control by 11:42 a.m. after mobilizing 33 fire trucks and 121 personnel. The flames were completely extinguished after two hours.

Thick black smoke engulfed the building at one time, prompting some 12-hundred visitors and workers at nearby offices to evacuate. Four people were treated for smoke inhalation but were not found critical.

The police and fire authorities plan to investigate to determine what caused the fire after completely extinguishing the flames.