Rescuers have recovered the bodies of three workers in a flooded tunnel under construction in a southern Chinese city and are continuing to look for the 11 other workers trapped since Thursday.
Crews also have been working to pump out water from the Shijingshan tunnel, which lies under a reservoir and was part of an expressway being built in the city of Zhuhai, in Guangdong province close to Hong Kong and Macao.
The rescue effort, also involving divers and robots, has been hampered by carbon monoxide fumes from machinery being used in the tunnel as part of the operation.
The cause of the collapse is still under investigation.
Reports said an abnormal noise was heard and bits of material started falling off on one side of the two-tube tunnel.
An evacuation was ordered as water rushed in.
The construction project appeared to have safety problems for some time.
In March, two workers died in another part of the tunnel.
Zhuhai is a relatively wealthy coastal city at the mouth of the Pearl River delta, which is now being heavily developed for manufacturing and high-tech industries.
It was one of China’s early special economic zones when the ruling Communist Party started opening up the nation’s economy about 40 years ago.