Tens of thousands have been left homeless in Cox's Bazar after fleeing.
Refugee aid groups estimate that between 40,500 and 50,000 people have been affected by the fire.
The settlement is part of a network of camps housing over a million refugees who have fled Myanmar since 2017.
"We still have 400 people unaccounted for, maybe somewhere in the rubble," UNHCR's Johannes Van der Klaauw, who joined a Geneva briefing virtually from Dhaka, Bangladesh.
