Thousands of people were evacuated from Bangladesh's southern coast and the officials warned ships of a cyclone roaring offshore.
The Bangladesh Meteorological Department issued a bulletin putting the low-lying country's three major maritime ports Chittagong, Mongla and Cox's Bazar on the highest level of alert.
Authorities suspended operations at the country's main seaport, Chittagong, while volunteers helped thousands of people move to cyclone shelters and other safer areas along the southern coast, state-run Bangladesh Television said.
The cyclone was in the Bay of Bengal, about 675 kilometers (420 miles) south-southwest of Cox's Bazar, with winds of up to 216 kph (134 mph), the bulletin said.
The southern seaside resort town of Cox's Bazar appeared deserted after the warning was issued Wednesday evening, an Associated Press reporter in the town said, adding that the sea was rough.
Bangladesh, a South Asian nation crisscrossed by river deltas, routinely suffers large-scale loss of life and property from cyclones and floods.