At a news conference on Wednesday, the prime minister, Thongloun Sisoulith, said that 131 people were still missing and more than 3,000 were homeless. Many had been rescued from rooftops and trees after villages and farmland were flooded.

At least 26 people have been reported killed.

“A second step for us will be to recover and identify the deceased, but for now, we hurry to find those who are still alive in the area,” Bounhom Phommasane, the governor of the district of Sanamxay, told The Vientiane Times.

Ms. Chantamart said that hundreds of people from her village had escaped, but that 15 people were still missing, nine of them children. She had been unable to reach their homes on Monday because the floodwaters had climbed too high.

“I’m very worried about them, from the bottom of my heart,” she said.

After she and hundreds of others scrambled to higher ground on Monday, soldiers and local officials moved them to the town of Paksong, west of the dam site, to take refuge in an empty warehouse normally used to store coffee.