At least 31 people have died and over 100 are still missing since an under-construction hydroelectric dam collapsed in southern Laos on July 23. The collapse caused flash floods through six villages, leaving more than 6,600 people homeless.

“The operation over the past day, teams have found bodies which put the death toll at 31 while the number of missing is at 130,” Deputy Governor of Attapeu province Ounla Xayasith said, according to AFP.

Rescuers retrieved a body from Ban Mai village and three from South Thahin village on Saturday, said Deputy Director General of the General Political Department Phalom Linthong, according to Xinhua News. Mai and Thahintai are among the six most severely-affected villages.

Phalom Linthong said that mud and the lack of equipment were obstacles to the rescue operations.

The dam was a joint venture between South Korean, Laotian and Thai firms and collapsed after heavy rains. Laos Minister of Energy and Mines Khammany Inthirath had said that poor construction may have contributed to the accident and the government would launch an official investigation.

A South Korean company involved in the project, SK Construction, said it would confirm possible compensation packages after the investigation is completed. “We will focus on relief efforts on the ground for now and will discuss any compensation packages once the investigative team announces the official result of their investigation,” a spokesperson of the company told AFP. The spokesperson said the firm has donated $10 million in aid.