SANAMXAY, Laos (AP) — Authorities are investigating the collapse of a dam in southeastern Laos that has killed at least 24 people and left 131 missing.

Floodwaters that had hit rooftops are receding Thursday as villages begin digging out from the deluge of mud from the dam's failure late Monday.

The state-run Vientiane Times says the thousands stranded in the disaster were rescued by Wednesday. It cites Lao Prime Minister Thongloun Sisoulith as saying Wednesday that more than 3,000 people were left homeless when the auxiliary dam of a joint venture hydroelectric project with two South Korean companies gave way after days of torrential rains.

Hundreds traveled by boat, bus and pickup trucks to shelters in nearby towns. The Red Cross, South Korean government and other organizations are rushing aid to the area.