At least 22 people died as the fiercest cyclone to hit parts of Bangladesh and eastern India this century sent trees flying and flattened houses, with millions crammed into shelters despite the risk of coronavirus.

Millions were left without power after Cyclone Amphan, packing winds of around 150 kilometres per hour (95 miles), carried away electricity pylons, walls and roofs, officials said Thursday as they began to assess the damage.

Bangladesh officials said at least 10 people had died, including a five-year-old boy and a 75-year-old man both hit by falling trees and a cyclone emergency volunteer who drowned.

Cyclones are an annual and growing hazard along the Bay of Bengal coast, claiming the lives of hundreds of thousands of people in recent decades.

Anwar Hossain Howlader, an official in the Khulna coastal district of Bangladesh, said a three-metre (10-feet) surge had destroyed embankments protecting villages despite locals toiling through the night.