The Indian Navy had reportedly kept its Eastern Fleet on the highest alert level to assist Bangladesh if needed.
Cyclone Mora made landfall in southeast Bangladesh on Tuesday, killing at least five people and forcing hundreds of thousands into shelters, emergency officials said. It comes after heavy rains in Sri Lanka caused landslides that killed at least 180 people.
The day before the cyclone made landfall, the Bangladesh Red Crescent activated its "Forecast-based-financing" mechanism, under which almost 3,000 households in Hatiya upazila, a low-lying area prone to flooding in the coastal district of Noakhali, received a grant of 5,000 taka (60 euros).
Previous year also, the coastal areas of Bangladesh were badly stricken by the cyclone Roanu when more than 24 people died in the natural calamity.
Away from the camps, authorities had evacuated more than 449,000 people to some 400 cyclone shelters as the storm approached.
Cyclone Mora smashed into Bangladesh's coastline around Cox's Bazar district early on Tuesday, packing winds up to 135km per hour (83 mph).More news: At least 13 dead in Turkish military helicopter crash
Squally winds speed reaching 45-55 km per hour gusting to 65 km per hour would prevail over South Assam, Meghalaya and Manipur and along and off West Bengal coast. When contacted, a United Nations official working with Rohingya refugees said the damage in the camps could not be assessed instantly. On account of this, which is expected to bring great devastation, Govt of Bangladesh is evacuating close to 1 million people to avoid casualties.
Three people have been killed by the cyclone.
Dozens of villages in the districts have reportedly been flooded and many susceptible houses have been damaged fully or partially.
Flight operations at Chittagong Airport were suspended.
The Meteorological Department of Bangladesh has advised all fishing boats and trawlers to not venture out into the North Bay of Bengal and to remain in the shelter of harbours till further notice, according to the Indian Express.
The Indian Navy has rescued 27 people in a major operation in Bangladesh which has been hit hard by Cyclone Mora, causing widespread destruction and rendering millions of people homeless.
"More people were still waiting for evacuation", CNN quoted Abu Syed Mohammad Hashim, acting director general of the country's Disaster Management Department, as saying.