Officials from the Mekong countries of Cambodia, Thailand and Vietnam are urging Laos to halt development of a dam project that could have a significant impact on downstream communities and ecosystems along the river.
Cambodian, Thai, and Vietnamese delegations visited the site of the planned dam on Wednesday. All three countries have expressed their concerns over the project.
Tek Vannara, head of Cambodia's NGO Forum, a consortium of organizations, told VOA Khmer he was still concerned after the visit to the Don Sahong dam site.
"If they block the fish migration passages by building this dam, some fish species will surely be lost," he said.
He added that the dam would affect at least 6 million Cambodians living either near the site or along the Mekong River or Tonle Sap lake.
Lao officials said they were conducting the project transparently and with the proper safeguards.
Sin Niny, permanent vice chair of Cambodia's National Mekong Committee, said Cambodia has maintained its position that Laos should stop the project and conduct more environmental assessments.
"We demand that Lao study in details as requested by other countries along the Mekong before starting the dam construction," said Sin Niny.
Meanwhile, more than 50 environmental and development organizations are preparing to submit a letter to the Mekong River Commission, an inter-regional body formed to tackle river issues, voicing their concerns over the impact of the dam.
This report was produced in collaboration with the VOA Khmer service.