Months of heavy rains have triggered widespread floods in northern and central Thailand, claiming at least 253 dead by Saturday and more than 3.5 billion dollars in damages. Floods have affected 30 of 77 provinces and 2.3 million people since July 25, the National Disaster Prevention Department reported. Prime Minister Yingluck Shinawatra on Saturday set up a war room to coordinate government response to the floods that have caused extensive damage to agriculture, industry, tourism, housing and public buildings. "The widespread flood problem is reaching crisis level, the worst in decades," she said in a television broadcast Friday night. Ayutthaya province, home of the former capital and a UNESCO World Heritage Site, has been inundated for days, submerging ancient pagodas as well as hundreds of factories in industrial estates. On Friday, the government was forced to close 10 kilometres on the Asian Highway, the main road from Bangkok, to avoid diverting more floodwaters to Ayutthaya and other central provinces. Meteorologists blamed the flooding on an unusually long La Nina weather cycle this year, which has resulted in the heaviest precipitation in decades. Cambodia, Laos, Myanmar and Vietnam have suffered similar flood destruction, with at least 150 people reported dead in Cambodia.