Cyclone Mora formed after monsoon rains triggered floods and landslides in Sri Lanka killing more than 200 people. Another three people drowned in the island nation when their makeshift raft capsized on Thursday.
The Bangladesh navy was on Thursday searching for 81 fishermen who went missing in the Bay of Bengal in the wake of Cyclone Mora.
The search follows the rescue of more than 63 people from the Bay of Bengal in the aftermath of a devastating cyclone that left several dead and thousands homeless.
"Still 81 fishermen are missing out of 144 fishermen. Bangladesh Naval Force have rescued 33 and Indian Naval Force rescued 30," said Mostaque Ahmed, head of the Cox's Bazar Mechanized Fishing Boat Owners Association.
Cyclone Mora, with wind up to 135 kph (85 mph) and heavy rain, hit southeast Bangladesh around Cox's Bazaar and the border with neighbouring Myanmar on Tuesday, leaving thousands of Muslim Rohingya refugees hunkered down in ruined camps.
Authorities in Cox's Bazar and neighbouring Chittagong district evacuated 350,000 people from low-lying areas before the storm roared in from the Bay of Bengal on Tuesday.
Cyclone Mora formed after monsoon rains triggered floods and landslides in Sri Lanka, off India's southern tip, killing 205 people in recent days, authorities said.
Raft capsizes in Sri Lanka
Three people drowned Thursday when their makeshift raft capsized in Sri Lanka.
Police said the victims, who included a mother and her 14-year-old son, ignored official warnings not to venture outdoors because they had a funeral to attend.
The drownings in Nagoda in the country's south follow the deaths of 203 people from Friday's heavy rains, most of them buried under landslides.
"We have appealed to the people not to go out to check their flooded homes without proper safety gear," navy spokesman Chaminda Walakuluge said.
The Disaster Management Centre said the situation across the country was improving and thousands of security personnel were working on relief and recovery operations.
The flooding is the worst since May 2003 when 250 people were killed and 10,000 homes destroyed after a similarly powerful monsoon, officials said.