Days of heavy monsoon rains have devastated large swaths of northern India and Bangladesh, killing at least 164 people, stranding millions and washing away vital crops, officials said Thursday.

Swollen rivers burst their banks and inundated parts of three northern Indian states and neighboring Bangladesh. The army was called in to evacuate people from 500 flooded villages in India's Uttar Pradesh state, said Diwakar Tripathi, a senior government official. He said valuable crops were destroyed.

"I have not seen such flooding in the last 24 years. It's a sheet of water everywhere," Santosh Mishra, who lives in Uttar Pradesh's Gonda district.

"There are no signs of houses, temples or trees," Mishra told local Sahara Samay television.

Some 14 million people in India and 5 million in Bangladesh have been displaced or marooned, according to government figures. At least 120 people have been killed in India, and 46 have died in Bangladesh.

Hundreds of thousands of people have fled to higher ground in India's Assam state, setting up makeshift dwellings. Government relief camps were housing about 100,000 people.

Atul Deka, a farmer in Assam, said he watched helplessly as swirling waters washed away the bamboo footbridge connecting his village to the road across the stream.

"We couldn't do anything as it happened in a flash. Now, we have to depend on the few row boats we have until the floods recede and we build the bridge all over again," he said.

Strong currents have cut off more than 1,600 yards of a highway in Assam's Dhemaji region and swept away a wooden bridge on the only alternate road, said Dibakar Misra, a government official in the region. Railway services were suspended because a long stretch of tracks was damaged.

Boats rescued people in waters 30 feet deep in some places, he said.

On Wednesday, 28 people died when an overcrowded boat evacuating them flipped and sank in a swollen river in a village in Uttar Pradesh.

In Bangladesh, a low-lying delta nation of 145 million people, schools and some government offices have been closed as streets were under waist-high water, local officials said.

Many displaced people have taken shelter on embankments, while others have moved onto rooftops of their houses. Residents were using small boats to get around.

Fakhruddin Ahmed, the head of Bangladesh's military-backed interim government, toured some of the flood-hit areas by helicopter Wednesday and promised to help.

"We know that you are suffering. Our government will do everything possible to reduce your miseries," Ahmed said.

India's Meteorological Department said unusual monsoon patterns this year led to heavier than usual rains in the affected regions.

"We've been getting constant rainfall in these areas for nearly 20 days," said B. P. Yadav, a spokesman for the department.

The monsoon season in South Asia runs from June to September. More than 1,000 people died last year.