Cyclone Mora has hit Bangladesh, lashing the country’s south-eastern coast with heavy rain and high winds.
The storm made landfall on Tuesday morning between the fishing port of Cox’s Bazar and the city of Chittagong, with winds of up to 117 km/h (73mph),
Authorities have been moving more than a million people to shelters.
India and Myanmar are also expected to be affected. It comes after heavy rains in Sri Lanka caused landslides that killed at least 180 people.
In Bangladesh, Cyclone Mora made landfall at 06:00 local time (00:00 GMT), the country’s Meteorological Department said.
It had previously warned that low-lying areas of Cox’s Bazar, Chittagong and many other coastal districts were “likely to be inundated” by a storm surge of 1.2m-1.5m (4-5ft) above normal levels.
Hundreds of thousands of people have been evacuated to shelters, schools and government offices.
Fishing boats and trawlers have been advised to remain in shelters. Flights in the area have been cancelled.
Tracking website Tropical Storm Risk forecasts that Cyclone Mora will move northwards past Chittagong, weakening as it moves further inland and downgrading from a Category One hurricane to a tropical storm.
No casualties have been reported so far, but the cyclone caused significant damage to refugee camps for Rohingya Muslims, community leader Abdus Salam said.
He told AFP news agency that 20,000 houses in refugee camps were damaged.
“In some places, almost every shanty home made of tin, bamboo and plastic has been flattened. Some people were injured, but no-one is dead,” Mr Salam added.
Large camps have been set up in Cox’s Bazar for hundreds of thousands of ethnic Rohingya who have fled violence in neighbouring Myanmar.
The Bay of Bengal is prone to storms, and Bangladesh is often hit by severe weather during the monsoon season from the middle to the end of the year.
Last year Cyclone Roanu hit coastal Bangladesh, leaving at least 24 people dead.