Mashco-Piro 'uncontacted' Peruvian tribe pictured

Chance encounters near an isolated Amazon tribe have resulted in the most detailed pictures ever taken of them.

Campaign group Survival International has released images of the Mashco-Piro tribe, which lives near the Manu National Park in southeastern Peru.

The tribe has had little if any peaceful contact with the outside world, but sightings are on the rise.

Survival blames the change on gas and oil projects and illegal logging in the area, pushing the tribe into new lands.

The message that the Mashco-Piro tribe seems to be sending, however, is that they want to be left alone.

"There's been increasing conflict and violence against outsiders that are on their ancestral land," Survival's Peru campaigner Rebecca Spooner told BBC News.

That violence has included arrows being fired at tourists in passing boats, and a warning arrow - with no tip - being recently fired at a Manu park ranger.

Most recently, an arrow attack by members of the tribe killed Nicolas "Shaco" Flores - a member of a different tribe who had been attempting to make formal contact with the Mashco-Piro for some two decades.

An account of the attack by anthropologist Glenn Shepard underlines the fact that the tribe is fearful of forming ties with the world around them.

So it was at a respectful distance of 120m that Spanish archaeologist Diego Cortijo snapped pictures of the tribe using a telescope mounted on a camera, capturing the most detailed images ever taken of such "uncontacted" tribes, many of whom are detailed at a site of the same name.

Ms Spooner suggested that the evident increase in violence could be abated by preserving the local tribes' traditional lands.

"We're asking the Peruvian government to do more to protect that land, which should be set aside for the uncontacted groups," she said.

Gabriella Galli spotted the tribe on a riverbank in August 2011