Cyclone Fani weakened to a depression as it barrelled into Bangladesh on Saturday after leaving a trail of deadly destruction in India, although a major human disaster looked to have been averted.
Press reports said 12 people had died in India and police in Bangladesh put the death toll there at the same number -- a fraction of the casualty numbers seen in past cyclones, earning authorities praise from the United Nations.
With 1.2 million evacuated in India's Odisha state, more than 1.6 million people were taken to shelters in Bangladesh, officials told AFP, with at least 36 villages flooded by a storm surge and more than 2,000 homes destroyed.
"Six people died after they were hit by falling trees or collapsed walls, and six have died from lightning," Bangladeshi disaster official Benazir Ahmed told AFP.
In the coastal town of Banishanta, where embankments burst and some 250 families were marooned overnight, most houses were semi-submerged under water while a few straw huts had been washed away.
"We are now trying to fix the dam otherwise we will have to pass the night outside," villager Sanjay Mondol told AFP.
Ferries on large rivers remained out of action but those on smaller waterways resumed operations, and many people were beginning to return home with the wind still strong and skies overcast.
India's Meteorological Department posted to Twitter Saturday that Fani had weakened to a depression over Bangladesh.
But the storm was still packing a punch, with winds of up to 70 kilometres (45 miles) per hour and heavy rain battering the Indian state of West Bengal, its capital Kolkata and the Sundarbans mangrove forest area overnight and on Saturday morning.
"It's a total mess in islands of the Sunderbans as the cyclone has destroyed everything in its path, fuelling fears rivers could burst their banks and leave vast areas underwater," said Manturam Pakhira, Sunderbans affairs minister.
"Several homes have been flattened, roofs blown off, electric poles and trees toppled."
In Kolkata, home to 4.6 million people, 5,000 residents were removed from low-lying areas and old, dilapidated buildings.
"Nearly a dozen people were trapped as an old building in the northern part of the city has collapsed," mayor Firhad Hakim said. "They have been rescued and shifted to a safer place."
Kolkata's airport was meanwhile reopened, as was that of Bhubaneswar, capital of Odisha, the Indian state whose 46 million people are among India's poorest and who bore the brunt of Fani.
- Flying trees -
Prime Minister Narendra Modi, hoping to secure a second term in India's ongoing election, tweeted that he would visit the state on Monday.
Fani made landfall in Odisha on Friday, packing winds gusting up to 200 kilometres (125 miles) an hour, sending coconut trees flying, knocking down power lines and cutting off water and telecommunications.
Twelve people were killed there, the Press Trust of India (PTI) news agency reported, including a teenage boy crushed under a tree and a woman hit by concrete debris.
"It just went dark and then suddenly we could barely see five metres in front of us," said one Puri resident. "The wind is deafening."
As Fani headed northeast, Odisha authorities on Saturday battled to remove fallen trees and other debris strewn over roads and to restore phone and internet services. Aerial pictures showed extensive flooding.
Gouranga Malick, 48, was solemnly picking up bricks after the small two-room house he shared with his family collapsed.
"I have never witnessed this type of devastation in my lifetime," he told AFP.
Eastern India is regularly buffeted by cyclones off the Bay of Bengal, with 10,000 people killed in Odisha alone in 1999, mostly from a storm surge bringing flooding and debris many miles inland.
This time better forecasting and mass evacuations helped to prepare Odisha, while no major storm surges were reported.
"Almost 7,000 kitchens catering to 9,000 shelters were made functional overnight. This mammoth exercise involved more than 45,000 volunteers," Odisha's chief minister Naveen Patnaik said.
"Now the technology has improved vastly," Mahesh Palawat of Skymet, a private weather forecaster, told AFP. "The administration got enough time of around eight days to prepare and allocate disaster response teams."
The UN Office for Disaster Risk Reduction (UNDRR) praised India, saying the accuracy of early warnings and "effective evacuation" of people in Odisha "saved many lives".