Yanomami Indians sit around a fire at the community of Irotatheri, during a government trip for journalists, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

Yanomami Indians sleep on hammocks at their shack at the community of Irotatheri, during a government trip for journalists, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

A Yanomami Indian dances at the community of Irotatheri, during a government trip for journalists, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

A Yanomami Indian boy looks on at a hammock at the community of Irotatheri, during a government trip for journalists, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 8, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 8, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

A Yanomami Indian runs in the jungle at the community of Irotatheri, during a government trip for journalists, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

An aerial view shows the Yanomami Indian community of Irotatheri, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, during a government trip for journalists, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY) 

A Yanomami Indian shack is pictured at night during a government trip for journalists at the community of Irotatheri, in the southern Amazonas state of Venezuela, just 19km (12 miles) from Brazil's border, September 7, 2012. The Venezuela government and indigenous groups are disputing whether an alleged massacre of Amazon villagers took place after the government said it found no evidence of an attack. A group representing the Yanomami tribe last week said that Brazilian gold miners had crossed the border and attacked a village from a helicopter. Venezuelan officials said over the weekend that flyovers of the area led them to believe that the allegations were false. Picture taken September 7, 2012. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS SOCIETY TPX IMAGES OF THE DAY) 

A doctor performs surgery on a man from the Yanomamy tribe at the Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state in northern Brazil, November 8, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditions) is made up of volunteer doctors who set up a mobile hospital in the Amazon Rainforest twice a year to give clinical and surgical attention to indigenous and local people. REUTERS/Ricardo Moraes (BRAZIL - Tags: ENVIRONMENT SOCIETY HEALTH) 

A man from a Yanomami tribe waits to be operated on by doctors from a "Expedicionarios da Saude" (Brazilian Health Expeditions) medical expedition to the Cartucho community in Santa Isabel do Rio Negro, in Amazonas state, northern Brazil, November 7, 2010. The organization carries out two annual expeditions to the Amazon Rainforest with voluntary doctors to provide clinical and surgical treatment for members of indigenous tribes and residents. REUTERS/Ricardo Moraes (BRAZIL - Tags: SOCIETY HEALTH) 

A man from a Yanomami tribe waits to be operated on by doctors from a "Expedicionarios da Saude" (Brazilian Health Expeditions) medical expedition to the Cartucho community in Santa Isabel do Rio Negro, in Amazonas state, northern Brazil, November 7, 2010. The organization carries out two annual expeditions to the Amazon Rainforest with voluntary doctors to provide clinical and surgical treatment for members of indigenous tribes and residents. REUTERS/Ricardo Moraes (BRAZIL - Tags: SOCIETY HEALTH) FOR BEST QUALITY AVAILABLE: ALSO SEE GM1E6CH08EI01 

Afonso (C), a man from a Yanomami tribe, is carried by medical assistants from the "Expedicionarios da Saude" (Brazilian Health Expeditions) medical expedition after his surgery to remove a cancer tumor at the Cartucho community in Santa Isabel do Rio Negro, in Amazonas state, northern Brazil, November 7, 2010. The organization carries out two annual expeditions to the Amazon Rainforest with voluntary doctors to provide clinical and surgical treatment for members of indigenous tribes and residents. REUTERS/Ricardo Moraes (BRAZIL - Tags: HEALTH SOCIETY IMAGES OF THE DAY) 

A doctor carries Evandro, an 8-year old child from a Yanomani tribe, after his surgery at Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state, northern Brazil, November 7, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditors) organization is made up of volunteer doctors that twice a year build a hospital to provide medical care for indigenous tribes and residents who come from different locations of the Amazonian Rainforest to receive clinical and surgical treatment. REUTERS/Ricardo Moraes (BRAZIL - Tags: SOCIETY HEALTH ENVIRONMENT) 

A woman from the Yanomami tribe receives treatment at Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state, northern Brazil, November 6, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditors) organization is made up of volunteer doctors that twice a year build a hospital to provide medical care for indigenous tribes and residents who come from different locations of the Amazonian Rainforest to receive clinical and surgical treatment. REUTERS/Ricardo Moraes (BRAZIL - Tags: ENVIRONMENT SOCIETY HEALTH) 

A member of a Yanomami tribe receives treatment at Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state, northern Brazil, November 6, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditors) organization is made up of volunteer doctors that twice a year build a hospital to provide medical care for indigenous tribes and residents who come from different locations of the Amazonian Rainforest to receive clinical and surgical treatment. REUTERS/Ricardo Moraes (BRAZIL - Tags: ENVIRONMENT SOCIETY HEALTH) 

A child from a Yanomami tribe receives medical treatment at Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state, northern Brazil, November 6, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditors) organization is made up of volunteer doctors that twice a year build a hospital to provide medical care for indigenous tribes and residents who come from different locations of the Amazonian Rainforest to receive clinical and surgical treatment. REUTERS/Ricardo Moraes (BRAZIL - Tags: ENVIRONMENT SOCIETY HEALTH) 

A doctor examines a child from a Yanomami tribe at Cartucho community during a medical expedition in Santa Izabel do Rio Negro, in Amazonas state, northern Brazil, November 6, 2010. The "Expedicionarios da Saude" (Brazilian Health Expeditors) organization is made up of volunteer doctors that twice a year build a hospital to provide medical care for indigenous tribes and residents who come from different locations of the Amazonian Rainforest to receive clinical and surgical treatment. REUTERS/Ricardo Moraes (BRAZIL - Tags: ENVIRONMENT SOCIETY HEALTH) 

File photo showing Yanomami Indians outside their Amazon jungle hut after burning and clearing the landscape, in the northern state of Roraima on March 16, 1998. The rate of deforestation in Brazil's Amazon rose 2.1 percent last year as farmers encroached on the world's largest jungle, the government said on April 7, 2004. The Amazon, an area of continuous tropical forest that is larger than Western Europe, has been described as the "lungs of the world" because of its vast capacity to produce oxygen. Environmentalists fear its destruction because it is home to up to 30 percent of the planet's animal and plant species and is an important source of medicines. Most of the deforestation takes place due to burning and logging to create farms. REUTERS/Gregg Newton/FILE GN