The Mashco-Piro are a nomadic people living in remote jungle in south- east Peru where the American oil company Mobil is carrying out seismic tests for oil.
Survival International, a British charity for tribal groups, which is monitoring the situation, say it is "inevitable" that many of the Indians will die from contact with common Western illnesses - such as whooping cough - against which they have no immunity. The group complains that despite the Mobil's promises to keep away from local people, there have been at least three "encounters" with them.
A local Indian representative group called Fenamad has taken statements from Indians about the exploration crews. The incidents outlined include helicopters flying low over Indian groups and a violent clash where the Mashco-Piro fired arrows at an exploratory team.
There are rumours that up to three workers have been killed in such battles - reports firmly denied by Mobil.
Jonathan Mazower, Survival's campaigns officer, said that 11 years ago when the Shell oil company and loggers had encountered related Indians in a neighbouring territory, at least half that population - up to 100 people - had been wiped out by disease.
"There is a tragic inevitability about what Mobil is doing," said Mr Mazower. "There is a very real danger that if there is any prolonged contact then some of these Indians will die."
He added: "These people have a right to be left alone. Both Peruvian and international law has recognised this."
Helen Newing, a biologist who has studied the situation, believes that the Mashco-Piro face disaster. "There is a real danger they could disappear altogether," she said.
The area of Peru where the people live, Madre de Dios, is split into two prospecting areas known as Block 77 and Block 78, each of about 1.5 million hectares, where the government has approved exploration.
Little is known about the mainly hunter-gatherer group, not even their name for themselves. They have been named "Mashco-Piro" as they appear to have a language which is similar to the Piro people. Ms Newing said there was evidence that the group had been trying to avoid outsiders, probably because they were aware of what had happened to their neighbours.
There may be a total of 1,500 uncontacted people in the area, including the Amahuaca and the Yaminahua groups.
Mobil yesterday denied there had been three encounters, and said that a detailed investigation at the weekend unearthed only two "events".
A spokesman at Mobil's headquarters in the US said that one of the events had proved to be a sighting of a loggers' village, rather than an Indian one, and in the other a person involved with seismic work had reported seeing a naked man with "black, straight, long hair" walking at a distance of about 30 metres.
He said the company's strict policy was to ensure no contact with the Indians, and that staff - including those among the subcontractors on seismic projects - were all given medical checks and environmental "sensitivity" training. A team of anthropologists and other experts was on stand-by in case inadvertent contact should occur.
"We want to reassure people that we are taking all possible steps to minimise the impact on people and the environment," the spokesman said.
A spokesman for Shell said the circumstances of the events in 1985 were not clear, but that any lessons learned would be incorporated into future projects.Reuse content