A cyclone slammed into parts of Bangladesh and eastern India on Monday, triggering tidal surges and flooding that forced some half a million people from their homes and killed almost three dozen people.
Storm officials in coastal Bangladesh moved about 500,000 people to temporary shelters after they left their homes to escape huge tidal waves churned by winds up to 60 mph.
Heavy rains triggered by the storm also raised river levels and burst mud embankments in the Sundarbans delta in the neighbouring eastern Indian state of West Bengal. The affected area is home to hundreds of thousands of people as well as the world's biggest tiger reserve.
The cyclone killed at least 33 people, including 18 in West Bengal, officials from the two countries said. Most victims either drowned or were killed in house collapses or crushed under uprooted trees.
Indian Oil Corp suspended operations of its single-point mooring facility at Paradip port in eastern India, while authorities shut down operations at Bangladesh's main ports of Chittagong and Mongla.
The cyclone and tidal waves damaged roads and embankments and levelled standing crops over vast areas, officials said.
"Another high tide is due. We fear that the situation may deteriorate," police inspector Mohammad Belayet Hossain said from Bangladesh's coastal Bhola district.
Salahuddin Chowdhury, a Bangladesh cyclone official, said: "Nearly 500,000 people who fled (their) homes have been sheltered in several hundred shelters in eight coastal districts so far."
About 400,000 people remained marooned in Sundarbans. "No assistance could be reached to them because of stormy conditions and turbulent rivers," said Kanti Ganguly, state minister for the Sundarbans.
"Our village is submerged, we are living in camps and have no clue what further calamity awaits us," Anil Krishna Mistry, a villager, told Reuters by telephone from Bali in Sundarbans.
Heavy rains caused flooding in the streets of state capital Kolkata as strong winds uprooted trees and communication lines. Television pictures showed rescue workers struggling to free a man trapped in his car.
Tourists were asked to stay in their hotels in West Bengal's southern coastal resort of Digha, four hours drive from Kolkata.
Tidal waves triggered by the storm in the Bay of Bengal damaged thousands of houses in Bangladesh, mostly in Khulna district near the Sundarbans.
The storm surge washed away dozens of shrimp farms and inundated rice fields in Bangladesh, which is battered by storms every year.
In November 2007, Cyclone Sidr ravaged a large part of the country's coast, killing nearly 3,500 people and displacing around two million.