Tens of thousands of people in Bangladesh and Sri Lanka need aid including clean drinking water, dry food rations and medicines after a deadly cyclone hammered the South Asia region, aid agencies said on Tuesday. With wind speeds reaching 90 kph (56 mph) and heavy rains, cyclone Roanu struck Bangladesh on Saturday, after buffeting India and Sri Lanka in the Bay of Bengal - killing at least 120 people and affecting hundreds of thousands more in the region. Aid workers said Roanu's torrential rains triggered flooding, landslides and tidal surges mostly in Sri Lanka and Bangladesh - ripping apart thousands of rickety homes, burying entire villages and inundating swathes of farmland. "Tens of thousands of poor families will have lost most of their assets - not just their houses, but also their food stores, seasonal crops and vital livestock such as cows, goats and ducks," said Shakeb Nabi, Christian Aid's Bangladesh head. "Access to food, safe drinking water, health supplies and sanitation materials is limited in some villages. Water points have been ruined, ground water contaminated and agricultural land destroyed." In Sri Lanka, where more than a week of heavy rains has triggered the worst flooding in 25 years, the United Nations said it was worried about the spread of diseases due to large amounts of standing water. The World Health Organization said there was an increased risk of vector borne diseases like malaria, water borne and diarrheal diseases, the bacterial disease leptospirosis, fungal diseases and acute respiratory infections. "Prevention measures to combat such diseases are essential," it added. Roanu is the first cyclone of the season, which generally lasts from April to December, with severe storms often causing mass evacuations from coastal low-lying villages and widespread crop and property damage. Rushing in Relief Aid agencies in Bangladesh and Sri Lanka said they had begun distributing relief in the worst affected districts and foreign aid had started arriving in Sri Lanka from countries including India, Pakistan and Singapore. Half a million people have had their lives disrupted in Bangladesh's low-lying coastal areas such as Barisal and Chittagong, and over 255,000 people are affected in Sri Lankan districts including Kegalle, Gamapaha and the capital Colombo in the west. "We have pre-positioned household materials and hygiene kits that we can dispatch to affected areas and distribute to communities in urgent need," said Senait Gebregziabher, country director for Plan International. "These materials will be essential as children and families affected by the cyclone, particularly those forced to leave their homes, will most likely be seeking food, shelter, basic sanitation and access to clean water." Sri Lanka has reported 94 deaths and 107 people missing. Bangladesh said at least 24 people had died and India reported two deaths. U.N. emergency officials said Roanu also brought heavy rains and flooding to coastal eastern and southern India and western parts of Myanmar, but the impact was less severe.