Authorities in the French overseas territory of Mayotte could still confirm only 31 deaths on Wednesday from Cyclone Chido, more than four days after it swept through the Indian Ocean archipelago, causing mayhem and killing possibly thousands.

Hundreds are feared dead after the storm razed entire neighborhoods in Mayotte, a series of islands off the eastern coast of Africa, before unleashing its destructive force on Mozambique.

France declared "exceptional natural disaster" measures for Mayotte on Wednesday as authorities grappled with the full scale of the devastation wrought by Cyclone Chido on the Indian Ocean archipelago,