Tens of thousands of villagers could be displaced and a fragile ecosystem destroyed by a hydropower project on northeastern Myanmar's Salween River, an international conservation group said Thursday.

Construction began earlier this year on the Ta Sang hydropower plant, which includes a dam, in a joint venture between Myanmar's government and Thai power producer MDX Group.

It is unclear when it will be finished.

WWF claims damming the Salween, one of Southeast Asia's last untamed rivers, will "displace and negatively impact upon tens of thousands of poor and marginalized people from ethnic minorities in that country."

"The Salween is the only free-flowing river linking the Himalayan glaciers to the coastline of the Andaman Sea," said a statement from Robert Mather of the WWF's Living Mekong Program.

"We are destroying the Salween before we even know what we're losing," Mather said. "From what little we do know about its large number of endemic fish species and abundance of freshwater turtles, we can conclude it is likely to be globally exceptional. "

A Myanmar government spokesman, Ye Htut, said the dam site is in a remote area and "very few people will need to be relocated for the hydro project."

"The Myanmar government will use every means to limit (the) environmental effect," he said by e-mail. "But we should not forget that industrialized countries have caused more damage to the environment then developing countries and have given very little assistance to environmental conservation works in developing countries."

A spokesman for MDX could not be immediately reached for comment.

Local environmental groups have said damming the Salween, called the Thanlwin in Myanmar, would degrade one of the area — a UNESCO World Heritage Site.

The government and DMX in April 2006 signed a US$6 billion (€5 billion) agreement to build the 7,110-megawatt plant about 480 kilometers (300 miles) northeast of Myanmar's biggest city, Yangon.

Most electricity from the project will be sold to neighboring Thailand. Myanmar, which faces constant power shortages, will get an unspecified amount of free electricity.

The dam projects is one of several planned on the Salween over the next 15 years.

Myanmar signed a memorandum of understanding this month with two Chinese firms to build a second hydropower plant on the river. It is unclear when construction would start.

WWF and other groups have urged Thailand to better manage its energy needs and invest in wind and biomass projects within its borders, rather than hydropower.

"It seems more reasonable for Thailand to rely on its own reserves of natural gas for energy security, than to be dependent on imports of electricity from a neighboring country with a high degree of political uncertainty, " Kraisak Choonavan, a former Thai senator, said in a statement.

Military-ruled Myanmar has drawn international criticism for stifling democracy and its poor human rights record. It has also long faced insurgencies among ethnic groups.