Opponents of the Lower Sesan II hydropower dam in Stung Treng province have called on the companies and the Chinese government to halt construction at the site.

Fifteen civil society groups and lawyers wrote to the Chinese government and the companies on Monday warning of social and environmental impacts that the dam will have on communities across the Mekong river basin.

The groups also demanded more accountability from all parties involved in the $816 million project, a joint venture between Cambodia’s Royal Group and China Huaneng Group.

The letters follow a meeting between Prime Minister Hun Sen and Cao Peixi, chairman of China Huaneng Group, where he reportedly called on the company to minimise the project’s impacts.

“Communities are reporting problems at the dam site which raise questions about legal compliance, such as logging outside of the reservoir area, unlawful fishing activities, use of child labour and deteriorating water quality downstream,” said Meach Mean, coordinator of the 3S Rivers Protection Network.