Rescuers battled thick mud and flood waters across a swathe of remote southern Laos to find survivors of a deadly dam burst that submerged entire villages, as an official suggested faulty construction may have led to the disaster.

The exact number of dead and missing from Monday’s dam collapse remains a mystery because of the complexity of the rescue operation in an inaccessible area and the secretive reflexes of Laos’ Communist authorities in the face of an unprecedented crisis.

“The search is very complicated, many areas cannot be accessed by cars or boats. Also we have limited modern equipment to bring to the field,” deputy secretary of Attapeu province committee Meenaporn Chaichompoo told reporters Friday.

The head of the rescue mission Kumriang Authakaison said Saturday that eight people are confirmed dead, down from 27 reported by officials earlier this week. He added that 123 were confirmed missing.

But conflicting information swirled about how many remain unaccounted for after Chaichompoo said Friday “we can’t find 1,126 people”, without elaborating.

Makeshift shelters are packed with thousands of people who fled their homes in panic with just a few hours’ notice of the impending disaster, now spending their days on plastic mats waiting for news of missing neighbours.

All karaoke bars and entertainment venues were ordered to tone down loud music and celebrations in the province as the nation mourned the calamity, the most devastating to hit Laos’ contentious hydropower sector.

A stretch of land dozens of kilometres long and wide was submerged when the Xe-Namnoy dam collapsed after heavy rains.

Slowly retreating floodwaters have cut off access to villages and covered much of the area with thick, sticky mud.

“This is one of the worst [disasters] I’ve ever seen. Especially because we’re not a very strong country in terms of rescue operations,” a volunteer rescue worker told AFP, requesting anonymity as he was not authorised to speak to media.

Poor construction?

Days into the treacherous search for survivors, questions are being raised about the quality of the construction of the $1.2 billion dam, a joint venture between South Korean, Laotian and Thai firms.

Operators said it burst after heavy rains in a country regularly battered by monsoons.

But Laos Minister of Energy and Mines Khammany Inthirath said poor design may have contributed to the accident, according to state media and Radio Free Asia.

“It might be construction technique that led to the collapse after it was affected by the rain,” he told RFA in an interview broadcast Friday.

One of the Korean firms involved in the project, SK Engineering & Construction, said it was investigating the cause of the dam break and would donate $10 million in relief aid.

The accident has kicked up criticism of Laos’ ambitious dam-building scheme as it bids to become a major power exporter, billing itself the “battery of Asia” with more than 50 projects set to go online by 2020.

The majority of energy generated in the tiny, landlocked country is sold to its neighbours, mostly to Thailand where much of it is sucked up in the sweaty, energy-hungry capital Bangkok.

Villagers have complained of being relocated – sometimes repeatedly – while river waters crucial for fishing and farming have been diverted, destroying livelihoods in one of Asia’s poorest countries.