Authorities and volunteers from aid agencies in southern Bangladesh are rebuilding shelters for thousands of Rohingya refugees who lost their bamboo-and-plastic dwellings to a devastating fire that killed at least 15 people, including children, officials said.

Thousands of refugees became homeless in Monday’s fire that raced through Balukhali camp at Ukhiya in Cox’s Bazar district, home to more than one million Rohingya refugees from neighbouring Myanmar.

The International Organization for Migration (IOM) said more than 10,000 families lost their homes. The fire also destroyed dozens of learning centres for children, clinics, markets and aid distribution centres.

“And it will take several months to put everything back to the level that it was prior to the fire,” said Manuel Marques Pereira, IOM’s deputy chief of mission in Bangladesh.

On Wednesday, different aid agencies supplied construction materials such as bamboo, rope, polythene, and corrugated tin sheets for rebuilding the shelters, officials said.

But the devastation was widespread and it could take a while to rebuild what was destroyed.

Pereira said easy access points for emergency services were important to avoid the loss of lives in the event of such disasters.

“The concerns over the capacity of the refugees to escape from the fire is a topic that needs to be linked with the congestion on the camps, and the shape of the camps, and the capacity of people to move in the camps,” he said.

“It is very important that there are access points for the emergency services and for the individuals to leave a certain area.”

Also on Wednesday, Bangladesh’s Home Minister Asaduzzaman Khan visited the camps to assess the situation. He said an investigation has been ordered to see if it was sabotage.

“I want to express our deepest sorrow for the people who have been affected by the fire,” he told the reporters.

The United Nations High Commissioner for Refugees said at least 400 people were still missing.

Bangladesh has given shelter to more than a million Rohingya, the vast majority having fled Buddhist-majority Myanmar in 2017 in a major crackdown by that country’s military.

The UN has said the crackdown had a genocidal intent, a charge Myanmar rejects.