The State Department says it is investigating reports of the three men.
Lao Police have been investigating their disappearance since early January.
Relocation compensation for the development project in the Lao capital is too low, the residents say.
Two months after the disappearance of a prominent activist, his family and friends hold prayers for his safety.
Authorities in Laos release a woman who had been held incommunicado for three months.
Rights groups say the disappearance of a Lao activist highlights Southeast Asia’s worsening rights record.
Plans move ahead for three hydropower dams in southern Laos.
Missing Lao activist Sombath Somphone's wife says authorities have failed to answer her questions about the investigation.