The worst monsoon floods in a decade to hit a remote northeastern Indian state have killed more than 80 people and forced around 2 million to leave their homes, officials said on Monday. Nearly half a million people are living in relief camps that have been set up across Assam state, Prime Minister Manmohan Singh told journalists in Gauhati, Assam\'s capital. The rest of the 2 million displaced are living in government buildings or in the open. Assam officials say 81 people have been killed over the past four days. Most of them were swept away when the mighty Brahmaputra River overflowed its banks and flooded villages. Sixteen people were buried in a landslide triggered by the rains. Air force helicopters were dropping food packets and drinking water to marooned people, Singh said after surveying the flood-hit districts. Army soldiers used boats to rescue villagers from rooftops of flooded homes. Teams of doctors have opened health clinics in the 770 relief camps that had been set up across Assam, one of India\'s main tea-growing states. The hilly tea growing areas have not been affected, but lower rice fields have been washed away. In the worst-hit Dhemaji district, raging waters of the Brahmaputra River swept away entire villages. Officials said the entire Majuli island, one of the world\'s largest river islands, was awash as water levels in the Brahmaputra rose above the danger level. \"This is one of the worst floods to hit Assam,\" Singh said. He announced the national government would give immediate assistance of Rs5 billion ($90 million) to the state. Officials say the situation was expected to improve over the next few days as the rain was tapering off and water levels were beginning to recede. Monsoon floods hit Assam, with a population of 26 million people, almost every year, with heavy rains swelling the Brahmaputra and its innumerable tributaries that crisscross the state.