Four workers are missing and presumed drowned after an under-construction dam partially collapsed in western Cambodia, officials said.
Major Theang Leng, chief of police in the district where the hydroelectric dam is located on the Atay river, said the collapse appeared to occur because the dam was holding too much water and had started leaking.
A search has got under way for the missing workers. Another four workers were seriously injured.
Theang Leng said construction work has been temporarily halted as experts survey the damage.
Although Cambodia has an electricity shortage, there has been criticism of building some dams for environmental and social reasons.
Yeat Thay, a mechanic who lives near the site, said the dam's reservoir was completely emptied by the accident. He said there were rumours that three to five Chinese experts involved in the construction were also missing, but Theang Leng denied this.
In a 2008 report, the US-based watchdog International Rivers Network said "poorly conceived hydropower development could irreparably damage" Cambodia's environment and also extract a social cost. In addition to being displaced, local villagers are also often deprived of the natural resources they used to depend on to make a living.
Work on the 120-megawatt Atay hydroelectric project began in 2008 and had been scheduled for completion in May 2013. The project is being undertaken by the China Datang Corp as a build-operate-transfer concession under which the company will operate it for 30 years.