At least 14 workers have been killed by collapsing scaffolding in Vietnam's Ha Tinh province, state media report.
About 30 other injured people were taken to hospital after the accident on a building site in the Vung Ang economic zone late on Wednesday.
Rescue workers have been searching the rubble for bodies and in case people were trapped.
The workers, all Vietnamese, had been subcontracted by a branch of South Korea's Samsung group.
One injured man said the scaffolding had started shaking an hour after they began work, and that many people had panicked and tried to escape.
"After 10 more minutes, the scaffolding which was about 20m (65 feet) high, suddenly collapsed. I quickly grabbed an iron bar but fell free," Dan Ninh Dan told the Associated Press. He was being treated in hospital for an injured hip.
"People were screaming, calling for help from the rubble," he said. "I was very lucky to survive."
A spokesman for the zone, Pham Tran De, said there had been thousands of people on the building site at the time "so the number of workers in distress is not yet accurately calculated".
"Authorities are actively removing the rubble to rescue the trapped workers," he said.
The Vung Ang zone was the scene of violent anti-Chinese protests last year amid heightened tensions over territorial disputes between China and Vietnam in the South China Sea.
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