PAKSONG DISTRICT, Laos — Bounna Eemchanthavong was trying to do math that refused to add up: About 650 people lived in his remote village in southern Laos before it was devastated by a dam failure, and only 65 of them had been spotted at two shelters where survivors gathered.
But local officials were telling him that only 10 people from the village were officially missing, Mr. Eemchanthavong, 61, said on Friday.
“I don’t know if that number is correct,” he said at one makeshift shelter, a converted primary school several dozen miles from his home, as other flood victims streamed past in a muddy field strewn with disposable food containers. “We’re just waiting for more information.”
The confusion has deepened with shifting and contradictory official statements.
On Friday, an official newspaper, The Vientiane Times, reported that the official death toll had “climbed” to four, contradicting earlier reports in the state-run media that had put the death toll at 27.
“It’s hard to know if they were lying now or if they were incompetent before,” said Ian Baird, an expert on Laos at the University of Wisconsin, Madison, referring to Laotian officials. But he said the confusion was to be expected, with a risk-averse authoritarian government in a poor country that is not accustomed to responding to disasters of this magnitude.
Also unclear were the scale of the search and rescue effort, and how well it was going. The state media has said that the dam failure made more than 6,000 people “homeless.”
But as of Friday, the government had not explained precisely how many of those newly homeless people — minus the 131 it said were officially missing — had been accounted for.
The United Nations said a day after the accident that about 1,494 people had been evacuated and registered at temporary shelters.
Meanwhile, in neighboring Cambodia, where floodwaters from the failed dam were causing flooding in the northern province of Stung Treng, the provincial government there said in a statement that 1,289 families had been evacuated. Cambodian state media had reported a day earlier that they were evacuating as many as 25,000 people. The reason for the discrepancy was unclear.
“The situation is not so serious yet,” said Mao Hak, the deputy director general of technical affairs at Cambodia’s Ministry of Water Resources.
The failed dam that was breached on Monday amid heavy rains is one of several dams in a billion-dollar hydroelectric project that is under construction. The state-controlled Lao News Agency has published two wildly different estimates of how much water was released, but even its lower one — roughly 17.7 billion cubic feet of water — would be enough to cover an area the size of Manhattan in water 28 feet deep.
The firm behind the project, Xe-Pian Xe-Namnoy Power Company, is a joint venture of two South Korean firms, one from Thailand, and a state-owned Laotian firm.
On Friday, the Lao News Agency quoted Khammany Inthirath, the minister of energy and mines, as saying that what the agency called the “collapse” of the dam was caused by “substandard construction.”
Richard Meehan, a former dam builder and former adjunct professor at Stanford University’s School of Engineering, said that the dam failure sounded to him like a case of “failure by internal erosion” caused by construction defects like inadequate foundation preparation, bad grouting, and high-risk design configurations.
“These are of course all the more likely when the project is deeply profit-driven, geographically remote, and managed by multiple entities with conflicting interests, poor communications, and zero patience for what they take to be fussy details or delays,” Mr. Meehan said in an email.
One of the South Korean firms, SK Engineering & Construction, said on Friday that it did not want to comment on the minister’s statement until the causes of the incident had been determined by a formal investigation. It said it would take responsibility if the investigation found the company was culpable.
“But right now, we are focused on relief efforts and minimizing the damage,” said Kwon Kyok-jin, a company spokesman.
A representative for the Thai company involved in the project, Ratchaburi Electricity Generating Holding, declined to comment on whether the construction of the failed dam was substandard.
At makeshift shelters across southern Laos, flood victims spoke of harrowing ordeals and searing losses.
At a shelter near the southern city of Paksong, a 30-year-old woman from the Talieng ethnic-minority group described losing her mother in the floodwaters. “My husband couldn’t hold on to her, so she got swept away,” said the woman, Phorn, who goes by only one name.
Sone Saenkanya, 43, said that 40 or 50 people from his village, Kaeyai, were still missing. “I think all those people are dead,” he said, his eyes bloodshot, standing on the porch of the converted primary school in a green sweatshirt.
Back in a flood zone near the dam, a five-hour drive from the shelter on rutted roads, the waters were beginning to recede. But the scenes there were anything but normal.
Inside, Ms. Wanphaeng, who goes by only one name, found shattered bottles, broken auto parts and a basket holding three dozen eggs. She began to clean off the mud with a dirty rag.
“This is all we have,” she said.