Mayotte was placed on a red weather alert from 1900 GMT on Saturday in anticipation of the passage of Cyclone Dikeledi to the south of the territory.

Authorities called for "extreme vigilance" following the devastation wrought by Cyclone Chido in mid-December.

Meteo-France predicted "significant rain and windy conditions", saying that very heavy rain could cause flooding.

Residents were advised to seek shelter and stock up on food and water.

The storm is expected to reach the northeastern coast of Madagascar on Saturday evening before moving off the coast of southern Mayotte on Sunday, according to forecasts.

"Nothing is being left to chance," Manuel Valls, France's new overseas territories minister, told AFP, referring to forecasts of "heavy and continuous rain" and winds of up to 110 kilometres per hour.

The most devastating cyclone to hit France's poorest department in 90 years caused colossal damage, killing at least 39 people and injuring more than 5,600 in December.

"We need to be seriously prepared for the possibility of a close passage of the cyclone," the Mayotte prefecture said on X.

Prefect Francois-Xavier Bieuville, the top Paris-appointed official on the territory, said Mayotte would be placed on a red weather alert from 1900 GMT on Saturday

"I have decided to bring forward this red alert to 10:00 pm to allow everyone to take shelter, to confine themselves, to take care of the people close to you, your children, your families," Bieuville said on television.

Messages in French and two regional languages were broadcast on radio and television to alert the population.

Bieuville told reporters earlier Saturday that the cyclone was forecast to pass within 110 kilometres (70 miles) of the archipelago's southern coast.

"We even have systems telling us 75 kilometres. So we have something that is going to hit Mayotte very closely", he said.

- 'Very worried' -

However, forecasters expect the cyclone to weaken on Saturday night "to the stage of a strong tropical storm, before moving off the coast of southern Mayotte during the day on Sunday".

More than 4,000 personnel have been mobilised, including members of police and the army, said the interior ministry.

The prefect has requested that mayors reopen accommodation centres such as schools and gymnasiums that sheltered around 15,000 people in December.

He also ordered firefighters and other forces to be deployed to "extremely fragile" shantytowns in Mamoudzou and elsewhere.

Potential mudslides were "a major risk", the prefect said.

"Chido was a dry cyclone, with very little rain," he added.

"This tropical storm is a wet event, we are going to have a lot of rain."

Mayotte's population stands officially at 320,000, but there are an estimated 100,000 to 200,000 more undocumented inhabitants living in shanty towns that were destroyed by the cyclone in December.

In Mamoudzou, Camelia Petre, 35, said she would be sheltering in her house, which "held up during Chido."

She told AFP that she would be "taking in friends and colleagues who have lost their homes."

She was "very worried about the vulnerable population," she added.

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