Soldiers and aid workers scrambled to reach hundreds of thousands of people still stranded on rooftops, trees and specks of dry land more than two weeks after the Kosi River burst its banks in Nepal, transforming large parts of Bihar state into a giant lake.
The army sent more than 5,000 troops to join rescue efforts, while officials said more than half of the 1.2 million stranded had been rescued.
The massive relief effort was the first to deploy all three branches of India's military - the army, the navy, and the air force, said Prataya Amrit, a top disaster management official in Bihar state.
Amrit said with the extra forces they hoped to complete the rescue phase of the operations in two days.
But even as attention turned to housing and feeding the refugees, new areas were cut off, posing fresh challenges to the rescuers.
Strong currents were also hampering rescue efforts, with the military being extra cautious after one of their boats capsized on the weekend, killing 19 people, Amrit said.
The road linking Saharia village to the rest of the hard-hit Saharsa district washed away Monday. Those that could braved the fast-flowing neck-deep water, carrying bicycles above their heads and bags of clothes on their shoulders.
Some swam out into the stream dragging frightened cattle after them.
Relief efforts, while kicking into high gear, were haphazard amid the chaos.
"The water came on Saturday and since then no government officials have come to us," said Ram Bachan Rai, 60, a Saharia resident.
However, his village was visited by aid workers from UNICEF and the European Union who tried to work out how best to provide help.
"We are going from place to place trying to assess the needs of the people, see what gaps there are and how we can fill it," Malini Morzaria, of the European Commission's Humanitarian Aid department, said as she waded through knee-deep water to reach one cut off hamlet.
Nearby, the government had set up a camp in a school, where some 1,000 people huddled together, with their cattle and goats.
Here, the refugees were getting shelter, medical treatment and three meals a day of cooked rice and lentils. There was a water pump with clean water where mothers were vigorously scrubbing the tepid flood waters off their children.
However, there was not enough room for all the refugees and dozens more set up camp under a large tree, while others staked a claim to a nearby gas station.
"Influential people are taking all the relief materials," complained Rajendra Sah, 43, one of those living under the tree.
As frustration grew among the homeless, there were reports of attacks on government officials and looting.
In Madhepura, one of the biggest flooded towns, residents stormed a government office late Monday throwing stones and demanding food, television news reports showed.
In Saharia, one man said local thugs had stolen their vital stores.
"People came in a boat and took away the grain we had stored on the roof," said Chetu Yadav, 28. "They were armed so we were afraid to challenge them."
With the numbers in the camps expected to nearly double in the coming days, there were fears the crowded and often-unsanitary conditions could lead to outbreaks of diseases such as cholera.
Officials say the flooding is expected to continue until November when the last of the monsoon rains taper off. Only then will they be able to plug the breach in the Kosi River that is more than a mile (kilometer) wide and growing.
The river, which flows down from the Himalayas into India where it joins the Ganges River, dramatically changed course after the breach, moving dozens of miles to the east and turning hundreds of square miles of land into a virtual lake.
Officials don't yet have a precise tally of those killed, but estimates range from scores to thousands.
Meanwhile in the northeastern state of Assam, monsoon floods submerged roughly 1,500 villages, drowning 15 people and displacing hundreds of thousands, said the state's Relief and Rehabilitation Minister Bhumidhar Barman. State authorities were working hard to reach affected areas, Barman said.
Two of Assam's major rivers, the Brahmaputra and the Barak, are flowing above the danger levels at more than a dozen places, according to a bulletin issued by the Central Water Commission, a federal flood monitoring agency.
The monsoon season, which starts in June, brings rain vital for the farmers of South Asia but also can cause massive destruction.
In neighboring Bangladesh, flooding has cut off at least 50,000 people, news reports said Tuesday, as a flood warning agency forecast the situation was "likely to deteriorate." News reports said three people drowned Monday in flood-ravaged areas north of the capital of Dhaka.