In a petition over the fertiliser plant, 25 associations, including the Tunisian Human Rights League, called for "the dismantling of polluting units and the establishment of an alternative regional development model to slow death and pollution".

The document highlighted "cases of asphyxiation among 69 children and students and four women" in the Chatt Essalem area of Gabes, as a result of "leaks of deadly toxic gases from the GCT (Tunisian Chemical Group), whose emissions have intensified since early September".

On Friday and Saturday, hundreds of residents gathered near the huge GCT factory to protest against its polluting emissions, after videos were released showing children in respiratory distress at a local school.

These were "peaceful protests", Khayreddine Debaya, a long-time activist with the Stop Pollution collective in Gabes, told AFP.

He explained there had been "clashes until midnight" after "the police dispersed the demonstrators with tear gas".

Roads were blocked and individuals attempted to set fire to a part of the GCT building, according to local media.

The Gabes local council on Sunday said it supported the "legitimate" demands of the protesters and called for the "dismantling of polluting chemical plants", while also criticising "acts of vandalism and violence".

Tunisian President Kais Saied said on Saturday he had dispatched an emergency team from the energy and environment ministries to monitor the situation closely.

Kais also said he wanted "a green Tunisia free of all pollution".

Debaya criticised the president's move saying it was time "to make decisions, not to send commissions".

Phosphate mines are Tunisia's principal natural resource, but for years activists have warned about the pollution caused by the GCT, which dumps its gaseous and solid waste directly into the environment.

Authorities have been caught between efforts to develop the strategic sector and a 2017 promise to gradually close the Gabes plant.