Devastating floods triggered by monsoon rains have killed more than 950 people and affected close to 40 million across northern India, southern Nepal and northern Bangladesh, officials said on Thursday.
The rains have led to wide-scale flooding in a broad arc stretching across the Himalayan foothills in the three countries, causing landslides, damaging roads and electricity pylons and washing away crops and tens of thousands of homes.
The northern Indian states of Bihar, Uttar Pradesh, West Bengal and Assam in the remote north-east are the worst hit, accounting for 680 deaths, most of them from drowning, snake bites or landslides.
South Asia's monsoon rains run from June to September.
Disaster management authorities in Bihar said the state's death toll of 367 could go up further as floodwaters recede and bodies are recovered from submerged houses.
Soldiers and volunteers have moved about 770,000 people away from inundated areas. Of these, about 425,000 are living in 1,360 relief camps set up in school and government buildings, said Avinash Kumar, a Bihar state official.
In neighboring Uttar Pradesh, the state government said about 2.3 million people in 25 districts were affected by flooding caused by at least three major rivers overflowing their banks.
An Uttar Pradesh government spokesman blamed the unprecedented flooding on the release of water from dams in upstream Nepal.
"Rains have been intense but the release of water from Nepal has aggravated the situation," said Manish Sharma.
Troops have been helping to rescue people marooned on rooftops or trees, while air force helicopters dropped packets of food, drinking water and medicines to those camping on higher ground, mostly along highways.
Meanwhile, the state administration was bracing for the threat of infections as floodwaters recede. Health workers have begun sending supplies of mosquito repellent, bleaching powder and water purification tablets to the worst-hit areas, said health official Badri Vishal.
In the eastern state of West Bengal, the head of the state government said 152 people had died and 15 million had been affected by floods in the past few weeks.
Another 71 people were killed in Assam as rivers breached their banks and entered low-lying villages. At the renowned Kaziranga National Park, about 300 animals including around two dozen rhinos and a Royal Bengal tiger have died after floodwaters submerged nearly 80 per cent of the wildlife reserve, officials said.
In neighboring Bangladesh, the death toll climbed to 132 while some 7.5 million people have been affected in this year's floods, according to the disaster management ministry.
Crops on more than 10,000 hectares of land have been washed away while another 600,000 hectares have been damaged, posing a serious threat to food production, the ministry said.
The UN World Food Programme said delta nation of 160 million people was at risk of "devastating hunger".
"Many flood survivors have lost everything: their homes, their possessions, their crops," said Christa Rader, WFP's country director for Bangladesh. "People need food right now, and the full impact on longer-term food security threatens to be devastating."
Nepal's home ministry said floodwaters were receding and river levels were returning to normal.
The death toll from the floods in Nepal stood at 146, with about 30 missing.