Firefighters work to rescue people trapped in debris after a collapse at the construction site of the Gwangju Metropolitan Library in Chipyeong-dong, Seo-gu, Gwangju, Thursday. (Yonhap)
Firefighters work to rescue people trapped in debris after a collapse at the construction site of the Gwangju Metropolitan Library in Chipyeong-dong, Seo-gu, Gwangju, Thursday. (Yonhap)

A steel structure collapsed at a library construction site in the southwestern city of Gwangju on Thursday, trapping a presumed four workers, including one who was rescued in critical condition, authorities said.

Firefighting officials said they were trying to rescue the workers while also checking for additional casualties. The accident occurred at 1:58 p.m. (Yonhap)