GWANGJU -- The chief of Hyundai Development Co. apologized Wednesday over the collapse of a facade of a high-rise apartment building under construction, which has left six workers still missing.

The exterior wall of the apartment building in the southwestern city of Gwangju crumbled down at around 3:46 p.m. Tuesday, with at least one person injured and about 10 vehicles buried under the rubble.

A total of 394 people were working at the scene of the accident, but six of them were unaccounted for, although their mobile phones received network signals near the scene, according to the police.

Hyundai Development is the main contractor for the construction project.

"We deeply apologized to missing workers and their families, and Gwangju citizens... We are thoroughly responsible for the accident," Yoo Byung-kyu, chief executive of Hyundai Development, said in a press conference near the construction site in western Gwangju, 330 kilometers south of Seoul.

Rescue workers temporarily stopped searching the rubble for any other victims due to concerns that remains of the facade and a tower crane could collapse, and they will decide whether to resume the search after conducting safety checks.

In June last year, Hyundai Development was also involved in the collapse of a five-story building demolished in Gwangju, killing nine bus passengers. (Yonhap)