GWANGJU-- The second day of search efforts ended fruitlessly Wednesday for the six workers who went missing after the collapse of a facade on a high-rise apartment building under construction in a southwestern city.

The rescue team employed nine drones equipped with thermal imaging cameras, six sniffer dogs and 15 personnel to rescue the workers, according to an official at a fire station in Gwangju. It plans to resume the search on Thursday.

"Due to the risks of the collapse (of the building), we halted the search in the evening. It will resume the following morning," the official said.

Exterior walls of the building under construction in Gwangju, 330 kilometers south of Seoul, crumbled a day earlier, trapping construction workers nearby.

Three workers were rescued in the initial search operation, with one of them sustaining injuries from falling rubble.

Six who were working on upper floors of the building, however, remain unaccounted for.

Search efforts at the collapse site were temporarily suspended Tuesday night due to safety concerns over possible further disintegration of the building or the potential collapse of a tower crane adjoining the building.

The rescue team resumed the search on Wednesday morning.

Mobilizing safety specialists and two drones, city authorities conducted a safety inspection in the area and gave safety clearance for rescue workers to resume operations in the morning.

The city government of Gwangju ordered the suspension of all ongoing construction work by HDC Hyundai Development Co., the main contractor of the construction project, within the city as it plans to open a probe into the cause of the deadly accident and those responsible.

City officials also pledged to make all possible administrative efforts to find the missing workers.

Source: Yonhap News Agency