Colombo, Dec. 1 -- Rescue workers in Sri Lanka are struggling to reach communities devastated by Cyclone Ditwah, as the official death toll climbed to 355 and a further 366 people remained missing on Dec 1.

Authorities say more than half a million people require immediate assistance, with the scale of destruction continuing to grow.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) estimates that 998,918 people across all 25 districts have now been affected by the flooding and landslides triggered by the cyclone landfall on November 28 before moving back over the Bay of Bengal.

Cyclone Ditwah brought the island's worst flooding in a decade, unleashing torrential rain and setting off deadly landslides in the central highla...