At least 345 people have been killed and hundreds injured in a stampede at a major festival in Cambodia’s capital Phnom Penh. Authorities say most of the victims were crushed or suffocated when a crowd on an island in the Tonle Sap River panicked and rushed to cross a bridge. Witnesses say some people drowned after falling off the bridge into the river.The Cambodian Prime Minister Hun Sen described the chaos as the biggest tragedy to strike the country since the Communist Khmer Rouge ruled in a reign of terror in the 1970s. He ordered an investigation into the incident and declared Thursday a national day of mourning for the victims.