President Moon Jae-in on Friday extended his sympathy over the deaths of three firefighters killed in a warehouse blaze in Pyeongtaek this week.

Presidential Chief of Staff You Young-min visited the funeral altar earlier in the day and conveyed Moon's message of condolences to the bereaved families.

Moon said he "prays for the repose of the three firefighters who died while facing the flames with thorough responsibility and courage," according to You.

You said the government will come up with measures to prevent such an incident from happening again.

The fire at the seven-story warehouse in Pyeongtaek, 70 kilometers south of Seoul, was first reported Wednesday.

Authorities reportedly brought the blaze under control Thursday morning but the fire suddenly began to rise again later.

The three victims at the warehouse fire scene were unaccounted for on Thursday morning and their bodies were found later. (Yonhap)