At least 77 people have been killed and nearly two million affected by heavy monsoon rains that caused floods in India's northeastern Assam state, in what the prime minister on Monday called one of the worst such disasters to strike recently. The mighty Brahmaputra river and many of its tributaries have breached their banks after downpours, washing away thousands of homes mostly made of bamboo and straw, as well as roads, bridges and power lines. Authorities have given shelter, food and medicines to thousands of homeless people, and deployed mobile medical teams to prevent the outbreak of disease. "People of Assam are facing one of the worst floods in recent times," Prime Minister Manmohan Singh told reporters in Guwahati, Assam's main city, after flying over the areas affected by the flooding. Floods have hit Assam - a state famous for its hilly tea-growing areas - at the same time that much of India has suffered weaker-than-average monsoon rains that are crucial to its hundreds of millions of farmers. Hundreds of soldiers and rescue workers from the federal National Disaster Response Force have been deployed for rescue and relief efforts, while military helicopters have airlifted people and dropped food.