At least six people have been killed and 36 fishermen reported missing as Cyclone Bulbul lashed Bangladesh overnight.
Some 30 people have been injured and around 6,000 homes partially or fully damaged, authorities added.
Cyclone Bulbul, packed with wind speeds of about 120 kmph, has left some low-lying areas flooded.
Nearly two million people from coastal districts have been moved to about 5,558 shelters late Saturday, with officials adding that prompt evacuations have helped save lives.
Meanwhile, efforts are on to rescue about 1,200 domestic tourists who were stranded at the Saint Martin island in the Cox's Bazar district.
"With the signal down to 4 all of them will be rescued," an official said, referring to a storm-warning system.
"It may take couple of days to get a normal situation," the country's junior minister for disaster management and relief told Reuters.
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