Many of those who found solid ground are still awaiting food
Relief efforts are increasing in the Indian state of Bihar, hit by some of the worst flooding in years.
Authorities say they have so far rescued more than 300,000 people left stranded after heavy monsoon rains caused the Kosi river to flood.
However, more than twice that number are still homeless and in urgent need of aid, and relief is being hampered by extensive damage to roads.
The waters have affected vast numbers of people in India and Nepal.
The BBC's Sanjoy Majumder, in Bihar, says extra boats have been pressed into service and additional troops deployed.
Rescue teams are still to reach some remote villages and have been dropping aid to from the air to those affected.
In some areas the water level has begun receding but the floods have also spread to other districts, affecting yet more people.
The forecast is for more rain in the coming days and the continuing bad weather is hampering efforts to get aid to about 2.5 million people who have been displaced.
More than one million people are now being housed in relief camps, where they are being given cooked food, water and medicines.
But many of the camps are already overflowing and there are more people streaming in by the hour, our correspondent says.
Aid workers estimate that many will have to live in temporary shelters for months until their homes and villages are rebuilt.
Amid relief efforts, the suffering of many of those affected continues. On Saturday at least 20 people were killed when a boat capsized while carrying dozens of police.
Damian Grammaticas describes the scene as people flee towns and villages
Indian PM Manmohan Singh, who visited the affected areas in Bihar on Thursday, said the flooding was a "national calamity".
He has announced an aid package worth $230m (£115m).
But aid agencies say many of the victims are being moved to temporary shelters which lack basic amenities.
A report released by Unicef says there are fears of infectious diseases at the camps.
Army and air force helicopters are continuing to provide aid to the flood-ravaged parts and 600 boats are helping with the relief and rescue work.
But the floods have washed away roads and railway tracks, and water and electricity supplies have been affected in many areas.
"This situation is beyond comprehension," Bihar resident, Arshad Khaqani, told the BBC News website.
The Kosi river flows from Nepal where it is called the Saptakoshi river.
On 18 August a dam on the Saptakoshi burst, triggering the subsequent flooding in Bihar.
Officials in Nepal say hundreds of people there have been hit by illnesses such as diarrhoea and pneumonia and an estimated 50,000 are homeless.
They say nearly 1,000 houses have been completely destroyed. Power supplies and transport have been severely affected.
The costs to the economy are now estimated at one billion Nepalese rupees ($14.25m).
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