The member of the gendarmerie’s GIGN, its elite tactical unit, was killed during the operation in Dorlin in the centre of the French territory, said a source close to the matter, asking not to be named.

The Actu17 website, which first reported the incident, said it took place overnight Friday to Saturday.

The French presidency in a statement confirmed the officer, named as Arnaud Blanc, had been killed and said President Emmanuel Macron “hailed his courage” and presented condolences to his partner and two children.

It said that the operation had been conducted jointly with French armed forces deployed in the territory.

Macron had asked the responsible government ministries to continue the fight against the “scourge” of illegal gold mining in Guiana, it added.

French authorities fear the illegal gold extraction is a major source of pollution into sensitive water systems.

In 2022, the French authorities carried out more than 1,000 patrols in the Guiana forest against illegal gold mining, seizing 59 kilograms (130 pounds) of mercury and five kilograms of gold, according to a report from local authorities.

Local mining operators say 10 tonnes of gold are illegally extracted from French Guiana each year by unauthorised gold miners known locally as “garimpeiros”.

French Guiana is one of several significant overseas territories which remain part of France and span South America to the Indian Ocean to the Pacific.