BANGKOK — A villager protesting the expansion of a Chinese copper mine in Myanmar was shot and killed on Monday, witnesses said, in the latest bout of violence to mar the project.

Villagers reached by telephone said the slain woman, Daw Khin Win, 56, was shot by security forces as the police and Chinese employees of the mine were erecting a fence in one of the villages where land had been seized for the expansion of the operation. More than a dozen people were wounded in clashes with security forces, witnesses said.

U Ye Htut, the spokesman for the government of Myanmar, said the police were “attacked by villagers” as construction of the fence got underway. “Tension has been building for weeks,” he said.

Cao Desheng, a spokesman for the project, said in an email that the “events leading up to her death are still unclear.”