VIENTIANE, Aug. 25 (Xinhua) -- Heavy rainfall and flash floods triggered by torrential rains in this monsoon season have affected many areas in Laos. Villages along the Mekong River and its main tributaries were recently warned to be alert for rising water levels. Earlier this month, river flooding hit four northern provinces in the Southeast Asian country, with roads flooded and water and electricity supplies cut off in some areas, authorities said. Heavy rainfall has also affected the capital Vientiane, which is located on the banks of the Mekong.