SANAMXAY, Laos, July 29 (Xinhua) -- Nine people were confirmed dead while 122 still missing after a dam collapsed, triggering flash flood in southern Laos on Monday, a provincial official said on Sunday.

Minaphone Saisomphu, deputy party committee secretary of Attapeu Province, deputy commander of the rescue operation, confirmed the deaths with media at a press conference on Sunday.

According to her, one body was found on Sunday, bringing the death toll to 9.

Minaphone told Xinhua earlier that the "missing" here means these people were swept away by floods and the figure was based on the reports from local villages.

The collapse of the under-construction Xepian-Xe Nam Noy hydropower dam caused flash flooding in several villages of Sanamxay district.

Being constructed by Xe Pian-Xe Namnoy Power Company, a joint venture of South Korean, Thai and Lao companies, the hydroelectric power project is estimated to cost 1.02 billion U.S. dollars, and to have an annual electricity generation of approximately 1,860 GWh.

Feasibility study for the hydroelectric project was completed in November, 2008. Construction of the project began in February 2013 and commercial operations are expected to begin in 2018.