Around 4 million people have been affected, with many seeking shelter on bridges, rooftops and high ground.

"The floods situation has turned worse overnight," Bhumidhar Burman, a minister in Assam in India's northeast, said. "We have stepped up our relief measures on a war footing."

Officials in neighbouring Bangladesh said half a million people were stranded in their homes while tens of thousands had found shelter in close to 100 relief camps.

The floods in the low-lying nation now cover half its area, with troops in boats providing medicines and food to some marooned residents and evacuating others.

The country's summer flood death toll crossed 160, with five more flood-related deaths reported, including three children.

GRAVEYARDS UNDER WATER

The deaths were the latest fatalities from storms, landslides and monsoon flooding in South Asia this month that has killed hundreds in India, Pakistan, Bangladesh, Afghanistan and Nepal.

Further east in Asia, deaths from floods, lightning and landslides across China this summer reached nearly 700, with 17 people killed in fierce storms and hail over the weekend.

Across eastern India, government buildings, small airports, military bases, hospitals and railway stations have been flooded, while the meteorological office warned of more rain.

Bihar's residents fear an epidemic as bodies cannot be buried or cremated with graveyards and cremation grounds under water.

Many highways were submerged, disrupting the movement of food and medicine. Air force helicopters were dropping food to marooned people, while schools were closed in many areas.

The situation was similar in Assam, in northeastern India.

The Kaziranga National Park -- famous for its one-horn rhinoceros -- was waterlogged, with floods forcing animals to move to the highway passing through the sanctuary.

Assam police launched a crackdown on traders selling food at inflated prices.

"Four traders have been arrested and warnings have been issued to others," a police spokesman said.