A state of exceptional natural disaster has been declared in Mayotte as the French Indian Ocean territory reels from the devastation of Cyclone Chido.

At least 31 people are reported by French officials to have died, while thousands are still missing after the cyclone tore through the small islands on Saturday.

It the first time this kind of emergency has been declared in France.

The move comes as President Emmanuel Macron was due to arrive in Mayotte on Thursday.

"We are waiting for him," said the French senator for Mayotte, Salama Ramia.

She told the BBC the priority should be to provide emergency food: "We hope that there will be food coming today or tomorrow, but it's really urgent.

"One or two shops have opened but not everybody has money to buy food, and even the shops are beginning to be empty, and so, the food for me is really urgent."

Designed specially for France's overseas territories, the emergency allows administrative barriers to be overcome in order to deal with the crisis more quickly and effectively.

It has been activated for one month, but can be extended by periods of two months if required.

"Faced with this exceptional situation, exceptional resources must be deployed to quickly restore vital services and implement a sustainable reconstruction plan for Mayotte," said the minister responsible for overseas territories, François-Noël Buffet.

Emergency services have been delivering food and water and clearing roads, while also racing to find the missing.

Health workers are concerned infectious diseases could spread, as residents have reported clean drinking water shortages and shops are rationing supplies.

The authorities have said their priority is to get damaged water plants back up and running.

Half the territory remains without power. A newly imposed curfew requires people to stay in their homes for six hours overnight to prevent looting.

Mayotte is one of the poorest parts of France, with many of its residents living in shanty towns.

Macron's administration has been criticised for underinvesting in Mayotte over a number of years.

It has been home to 100,000 migrants seeking asylum to France and living in informal settlements. They're believed to have been amongst those worst affected by the cyclone.

Chido - the worst storm to hit the archipelago in 90 years - brought wind speeds of more than 225km/h (140mph) on Saturday, flattening areas where people live in shacks with sheet metal roofs and leaving fields of dirt and debris.

After Mayotte the storm hit the African mainland, killing at least 45 people in Mozambique and 13 in Malawi.