Three Chinese engineers and an interpreter working on a major dam in eastern Burma have been released by an unidentified armed group after going missing three months ago.

The name of the group remains unknown, but is believed to have carried out the kidnap on 9 May in protest over the massive Tasang Dam being built by the China Three Gorges Project Corporation (CTGPC).

The Shan State Army (SSA), one of the principal armed groups operating in Burma’s largest state, said that it had negotiated with the militia for the release of the four men, all of whom were working on behalf of CTGPC.

“We inquired with the [militia] via local villagers and they said they weren’t looking for money but merely to show that they didn’t want the dam to continue,” said SSA spokesperson Sai Lao Hseng.

Like many of Burma’s energy projects, the Tasang Dam on the Salween River has been dogged by controversy and accusations that it has caused the displacement of thousands of Shan locals. Upon completion, it will be Southeast Asia’s tallest dam, pipping the Three Gorges Dam in China.

Until work began on the Tasang Dam, the Salween had been Southeast Asia’s longest undammed river. Local animosity against the project has long been virulent, with some 870 square kilometres of surrounding land expected to be flooded.

Sai Lao Hseng said that the milita had a message for those backing the dam. “[The militia] told us to inform the CTGPC and the Chinese and the Burmese governments that local people do not want the dam project to continue and that they would release the abductees if the dam project is stopped.

“So we informed the [company]. On 8 August, we learnt that the engineers were released.”

Many of Burma’s major hydropower projects are backed by Chinese companies are being constructed in the volatile border regions where fighting between anti-government groups and the Burmese army is escalating.