Large plumes of black smoke billowed into the sky after a fire broke out in the Rohingya Muslim refugee camps in Bangladesh on Monday.
The fire affected several refugee camps, with local reports saying at least three were severely damaged.
There are a little under one million refugees in the camps around the town of Cox's Bazar, on the south-east coast of Bangladesh.
The UN children's fund said it had mobilised resources to deal with the crisis, working with local fire services and volunteers.
The blaze appears to have spread across several blocks and damaged the Kutupalong camp – the world's largest refugee camp – and the Balukhali camp.
The Kutupalong camp is home to an estimated 626,500 Rohingya refugees, said the UN office for co-ordination of humanitarian affairs. They live in extremely inhospitable environment, housed in ramshackle huts.
The UK-based human rights organisation Restless Beings said about 70,000 refugees were affected by the blaze.
The extent of injuries has not been confirmed by authorities.
An activist at the scene of the fire told The National at least one person had died, but the toll was expected to rise.
Fire and medical personnel, including a number of volunteers, responded to the incident and rescued the residents.
The refugees, predominately Rohingya Muslims, were seen in photos posted on social media clutching at belongings they were able to salvage before fleeing the fire.
A large number of shelters appeared to be destroyed in the blaze, raising questions about where the refugees will now be housed.
In early March, Bangladesh transferred nearly 4,000 Rohingya refugees to a remote Bay of Bengal island, despite rights groups raising concerns about the site's vulnerability to storms and flooding.
The government dismissed safety concerns over the island, citing the building of flood defences as well as housing for about 100,000 people, hospitals and cyclone centres.
In August 2017, after a military crackdown in Myanmar, an estimated 750,000 Rohingya Muslims, a minority group in Myanmar, fled to neighbouring Bangladesh.