Deep in Brazil's Amazon rainforest, in a part seemingly unmarred by civilization, lives a secluded tribe.

Its people have lived quiet, unobtrusive lives, hidden from the eyes of the world for centuries -- until now, when researchers managed to capture them on camera for what is believed to be the first time ever.

Brazil’s agency for indigenous affairs, Funai, this week released video of several members of the tribe walking across a clearing in Vale do Javari, an indigenous territory in the state of Amazonas. The video was captured by a drone last year and gives a rare glimpse into the existence of the isolated tribe.

“These images have the power to make society and the government reflect on the importance of protecting these groups,” Funai's president Wallace Bastos said, according to an Associated Press report.

The video gives an aerial view of a patch of deforested area. A few people can be seen walking across the area in different directions, before re-entering the forest. One seems to be carrying a bow and arrow. At the edge of the clearing, a handful of people appear to be gathered together, as others pass them by on their way to and from the clearing. Dead trees are scattered across the cleared area. The tribespeople do not seem aware that they are being filmed.

For Funai’s researchers, they weren’t easy to find.

The team travelled more than 180 kilometres, sailing on rivers, riding on trucks on roads, and on bikes on closed trails, and walked another 120 kilometers on foot deep into the dense forest to get to them, the agency wrote in a Facebook post accompanying the video, adding that the tribe had been monitored before but was only captured on camera this one time.

“All this work is done to protect indigenous tribes,” it wrote.

Funai has registered 107 isolated tribes in Latin America’s largest nation, but it has a policy of not making contact with them, choosing to take videos and photos of them from a distance. Bruno Pereira, who coordinates Funai’s study of isolated groups in the region, told the Associated Press these communities are aware of the cities and farms in their surroundings, but they often choose to isolate themselves due to traumatic experiences with the outside world.

External contact can often be deadly, ending in massacres or epidemics wiping out tribes.

In July, Funai released footage of a lone survivor of a tribe, who became famous as the “world’s loneliest man”. He was believed to have been living in isolation for 22 years after the rest of his tribe was decimated by farmers.