A panic-stricken crowd - celebrating the end of the rainy season on an island in a river - tried to flee over a bridge and many people were crushed underfoot or fell over its sides into the water. Disoriented victims struggled to find an escape hatch through the human mass, pushing their way in every direction. After the stampede, bodies were stacked upon bodies on the bridge as rescuers swarmed the area.

The prime minister's special adviser, Om Yentieng, denied some reports that the victims were electrocuted by lighting cables and that the panic was sparked by a mass food poisoning.

Ambulances raced back and forth between the river and the hospitals for several hours after the stampede. Calmette Hospital, the capital's main medical facility, was filled to capacity with bodies as well as patients, some of whom had to be treated in hallways. Relatives, some crying, searched for the missing Tuesday morning.

"I was taken by shock. I thought I would die on the spot. Those who were strong enough escaped, but women and children died ," said Chea Srey Lak, a 27-year-old woman who was knocked over by the panicked crowd on the bridge.

She managed to escape but described a woman, about 60 years old, lying next to her who was trampled to death by hundreds of fleeing feet.

"There were cries and calls for help from everywhere, but nobody could help each other. Everyone just ran," she said at Calmette Hospital, where she was being treated for leg and hand injuries.

Hours after the chaos, the dead and injured were still being taken away from the scene, while searchers looked for bodies of anyone who might have drowned. Hundreds of shoes were left behind on and around the bridge. An Associated Press reporter saw one body floating in the river.

The government television station said 349 people had been killed and 500 injured. (AP)