Deep in the jungle in France's overseas territory of French Guiana, the army is engaged in a battle of attrition with illegal gold miners who have destroyed thousands of hectares of precious Amazon rainforest.
French Guiana, about the size of Portugal on the north shore of South America and almost completely covered in forest, has a long history of small-scale gold mining, legal and illegal.
But high gold prices have accelerated the scramble for the precious metal, with thousands of miners from neighbouring Brazil pouring across the border to try to cash in.
Their activity has left treeless brown gashes in the landscape, dotted with pools of water poisoned with the mercury used to extract gold from the soil.
Catching the illegal miners known as "garimpeiros" in the act is a nearly impossible task, but France is determined to try to protect its little corner of the Amazon.
- Burying the evidence -
On a small tributary of the Maroni river, the main waterway running north through Guiana to the Atlantic Ocean, French troops carry out a raid on an illegal mining site.
But by the time they arrive by canoe, guns at the ready, the miners have melted away into the forest after receiving a tip-off from lookouts.
The troops manage to apprehend two undocumented workers at the site but they were not caught in the act, so are freed.
Five soldiers in fatigues then scramble down a bank into the water-filled mining pit to search for hidden equipment.
Taking care not to splash their faces with the toxic liquid they fish out an engine and two mechanical pumps, which they destroy.
In a sign that the site could be reactivated soon after the troops leave, two men and two women wearing rubber boots linger nearby in the forest.
"If we destroy their material and they still come back it shows that this is an important site for them," said Staff Sergeant Olivier, whose full name was withheld for security reasons.
A child's shoe and a doll discarded on the ground suggested that this little community of outlaws includes children.
But in some places the garimpeiros, who use the gold to buy equipment from Chinese traders on the other side of the Maroni river in Suriname, are accused of bringing prostitution and violence into the forest.
"I've seen a four-poster bed, a mosquito net and condoms strewn everywhere" at one abandoned site, said Laura, a military police officer.
- Rivers poisoned -
Authorities in French Guiana estimate that 400 hectares of forest are destroyed each year by illegal mining, which threatens biodiversity in this relatively untouched part of the Amazon basin.
Arnaud Ancelin, deputy director of the Guiana Amazonian Park, a protected area covering 34,000 square kilometres (13,000 square miles) of rainforest, said the run-off from some mining sites created mercury-laced mud torrents "that block the gills of fish" and threaten the survival of their predators, including the otter.
The use of mercury, which has been banned in French Guiana since 2006, also poses major health risks for indigenous Amerindians, who have a fish-rich diet.
With 8,000 to 9,000 illegal miners believed to be operating at around 150 sites across the territory -- up from 110 a decade ago -- the nearly 1,000 French troops deployed to combat the prospectors are struggling to keep up.
- Tonnes of gold -
The garimpeiros are the smallest links in a chain, where those with their hands in the mud are paid a pittance while those in charge of transporting the gold race up and down the river in motorboats.
"We're only catching the little guys," French Guiana's public prosecutor Samuel Finielz told AFP.
Since January, the authorities have seized three kilogrammes of gold, a fraction of the roughly 10 tonnes believed to be illegally extracted each year.
But Finielz is adamant that the efforts are helping to prevent French Guiana's corner of the Amazon suffer the same fate as that of Brazil, which has endured massive deforestation.
"We're managing to contain illegal mining and in some instances reduce it," he said. "But we're not managing to put an end to it."