After a vicious cyclone this month razed slums housing many undocumented immigrants on the French island territory of Mayotte, Safina Soula did not shed a tear.

As the leader of an advocacy organization representing people from Mayotte, Ms. Soula staunchly supported an operation that the French authorities started last year to destroy the slums and deport undocumented immigrants, most of whom come from the nearby Comoros islands.

She hailed the cyclone as “a divine Wuambushu” — using the name of the slum clearance operation, and added, “Now the state must react quickly and forbid the reconstruction of these shantytowns.”

Cyclone Chido, which struck on Dec. 14 and killed at least 39 people, is inflaming already dangerous tensions over immigration on Mayotte, an archipelago off Africa’s eastern coast. After the disaster, France’s interior ministry said that nearly a third of Mayotte’s 320,000 residents were undocumented immigrants. Locals are calling for the government to ramp up efforts to deport them.

Many Mahorais, as locals are known, have long blamed immigrants for committing crimes and straining resources. Mayotte, where nearly 80 percent of the residents live in poverty, is the poorest place in France.

The people of Mayotte and Comoros share a common ancestry. However, in a decisive referendum in 1974, Mayotte was the only part of the Comoros archipelago that voted to remain part of France.