The prime minister’s special adviser, Om Yentieng, denied reports that the panic was sparked by people being electrocuted by lighting cables or by a mass food poisoning.
Authorities had estimated that upward of 2 million people would descend on Phnom Penh for the three-day water festival, the Bon Om Touk, which marks the end of the rainy season and whose main attraction is traditional boat races along the river.
The last race ended early Monday evening, and the panic started later on Koh Pich — Diamond Island — a long spit of land wedged in a fork in the river where a concert was being held. It was not clear how many people were on the island.
Soft drink vendor So Cheata said the trouble began when about 10 people fell unconscious in the press of the crowd. She said that set off a panic, which then turned into a stampede.
Seeking to escape the island, part of the crowd pushed onto the bridge, which also jammed up, with people falling under others and into the water.
A Singaporean businessman named Sonny who was running a sound-and-light show on the island Monday night said after people began collapsing firefighters sprayed the crowd, apparently to try to calm it down. Sonny, who asked not to use his surname so as not to jeopardize his business contacts, also said that it was at least 1½ hours after the bridge was mostly cleared before police and ambulances arrived.
Information Minister Khieu Kanharith denied that authorities fired water cannons.
Cambodia is one of the region’s poorer countries, and has an underdeveloped health system, with hospitals barely able to cope with daily medical demands. Hun Sen called on foreign investors and tourists not to shun the country because of the accident.
Koh Pich used to host a slum community, but in recent years the poor have been evicted to make way for high-rise and commercial development, most yet to be realized. When the slum dwellers were evicted, the area was handed over in 2006 to a company controlled by a tycoon connected to Hun Sen.