South Asia's worst floods in 15 years are receding after killing around 1,370 people across the region and should be over soon, weather officials said on Tuesday.
But tackling the devastation left by the flood waters and meeting the cost of rehabilitating people and infrastructure will be a daunting task for the authorities, officials and aid agencies said.
The flooding in mid-July caused damage worth about $7 billion in Bangladesh alone, the UN World Food Programme added.
"The floods wiped out people's household food stocks and effectively removed all other sources of nutrition and income. Fish farms are gone, poultry is drowned, fodder is unavailable for livestock so the animals are being sold at rock-bottom prices," the WFP said in a statement.
"WFP has mobilised its existing in-country food supplies to distribute rice and high-energy biscuits to 1.8 million people, while calling on donors to support the agency's steadily mounting relief campaign," the statement quoted WFP's country representative in Dhaka, Douglas Casson Coutts, as saying.
"We are getting strong indications that donors are prepared to be generous." Bangladesh's minister for food and disaster management, Chowdhury Kamal Ibne Yusuf, said the country has sufficient food and medicine to tackle the situation.
"We have taken measures to feed 20 million people free of cost until next March," he told journalists in Dhaka. The current floods and accompanying diseases have so far killed more than 1,370 people across South Asia, 660 in Bangladesh and the rest in India's Assam, Bihar and to a lesser extent, Gujarat state.
As flood waters receded in Bangladesh and eastern India, monsoon flooding in Gujarat killed 19 people in the past two days and left more than 20,000 stranded on rooftops of submerged houses, police said.
The dead included three children whose house collapsed in heavy rains in Borsad, about 70 km (44 miles) south of the Gjuarat's main city, Ahmedabad. The slowly progressing monsoon has hit parts of western and northern India since Monday.
In Bangladesh, homeless people waiting in long queues at a school compound in Old Dhaka jostled to grab cooked food and drinking water offered by local volunteers, witnesses said.
At Bosila on the capital's outskirts, CARE Bangladesh, the local arm of the US charity, is handing out 20,000 litres of drinking water daily to villagers marooned by the floods.
Coutts sounded a warning that, while the flood waters were now receding, "Bangladesh may well be in for a cataclysmic flood in mid-August, when the next monsoon rains will be unable to drain into the waterlogged ground".
"We have to be vigilant," he said.
Minister Yusuf agreed and said another major flood later this month could cause what he called a colossal loss to food production.
Coutts said later in an interview the WFP was co-ordinating plans by several UN agencies and NGOs to launch a "flash appeal" for aid.
Britain has offered $9.1 million in immediate flood aid. Unicef and the Federation of International Red Cross and Red Crescent Societies have made a global appeal for aid to save Bangladeshi flood victims, especially women and children.
Earlier on Monday Prime Minister Begum Khaleda Zia had said this year's flooding had a much more devastating impact on the economy compared with floods in 1988 and 1998.
"We have a much harder task ahead for rehabilitation of the people affected by the floods and of economy and infrastructure," she said while handing out relief supplies in a Dhaka suburb.
The 1988 floods killed about 3,500 people in Bangladesh, and more than 500 were killed in 1998.