Updated at 10 a.m. ET July 26

Several people reportedly were killed and hundreds of people were missing after the failure of a dam in the Xe Pian-Xe Namnoy hydroelectric project in southern Laos. The collapse of the dam, which is part of a larger dam network, has flooded villages and forced thousands of people to flee, state media report.

The full scale of the disaster isn't yet known.

The state news agency KPL initially reported that the collapse released 5 billion cubic meters of water, sweeping away several houses in the Sanamxay district of Attapeu province. It later changed that figure to say 0.5 billion cubic meters had been released.

Photos from the area show people crowded onto long boats to escape the high water, while others climbed onto rooftops with the belongings they could carry. Officials were asking neighboring provinces for assistance — and for anyone with a boat to help ferry people to safety.

The flash flooding happened Monday night, according to the state-sponsored Vientiane Times newspaper, which says a "saddle dam" was overcome at a reservoir for a power plant — part of an ongoing project to construct a series of hydroelectric dams in southern Laos.

"Some seven villages home to about 1,300 families and over 6,000 people were under water," the newspaper reports, citing the Attapeu Planning and Investment Department's director, Soulichanh Phonkeo.

Prime Minister Thongloun Sisoulith suspended a monthly government meeting to visit the stricken region and to review evacuation and relief efforts along with members of his Cabinet, according to KPL.

The Xe Namnoy River was diverted in April 2015 as part of the hydroelectric project.

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