Around half a million people are being evacuated to safer areas in south east Bangladesh, ahead of a cyclone that could be extremely dangerous.
Cyclone Mocha is predicted to make landfall on Sunday, with 170kph winds and storm surges of up to 12 feet.
There are concerns the cyclone could impact the world's largest refugee camp, Cox's Bazar, where close to a million people live in makeshift homes.
Rains are already falling on the camp and red warning flags have been raised.
Cyclone Mocha could be the most powerful cyclone seen in Bangladesh in nearly two decades.
As the weather system heads towards the Bangladesh-Myanmar coast, nearby airports have been shut, fishermen have been told to suspend their work, and 1,500 shelters have been set up, as the process of moving people from vulnerable areas begins.
Officials in Cox's Bazar said 1,000 people had already been evacuated from one area, with plans to move a further 8,000 people from a ward near the beach if the situation worsens.