(CNN) -- The Venezuelan government says it is investigating allegations that unauthorized Brazilian gold miners killed dozens of Yanomami Indians in an attack in the Venezuelan Amazon.
The announcement Wednesday followed calls for action this week by a Yanomami organization and other indigenous groups.
The Venezuelan government said that two public officials had been asked to carry out the inquiry into the alleged attack from a helicopter.
Survival International, a London-based organization that advocates tribal peoples' rights worldwide, published online what it said was a declaration from a group of organizations representing indigenous peoples and communities in the Amazon about the alleged attack.
The indigenous organization's declaration said that the number of people killed had yet to be fully established, but that of about 80 Yanomami people who lived in the community, only three survivors had been found.
The alleged attack on the community of Irotatheri in the Venezuelan municipality of Alto Orinoco, near the Brazilian border, is believed to have taken place in July. Survival said in its own report that information is only just beginning to emerge because of the remote location of the community.
The Yanomami, who live in Venezuela and Brazil, are considered the largest indigenous group in the Americas that remains largely untouched by advances in the outside world.
Anthropologists have described the tribe in a variety of ways, ranging from fierce warmongers to mystics to introspective intellectuals.
In recent years, the tribe has been under increasing pressure as miners illegally entered their land in the search of profits.
Miners in Brazil have transmitted diseases such as malaria and flu to the Yanomami, who have little resistance to such diseases, observers say.
The site where the attack is alleged to have happened is a five-hour helicopter ride, or 15 days on foot, from Puerto Ayacucho, the main Venezuelan city in the Amazon, the government said.
The harm caused to indigenous peoples and the environment by Brazilian gold miners working in the border area is a long-standing issue. The Brazilian police carried out an operation last month targeting miners operating on the Brazilian side of the border.
In its report on the situation, Survival cited Yanomami people who had spoken to Indians who said they had seen burned bodies and bones in the area where the attack is alleged to have happened.
One of the people it quoted, Luis Shatiwe Yanomami, a leader of the Yanomami organization Horonami, said he had been told that those who survived had been out hunting when the community's communal house was set on fire.
"For three years we have been denouncing the situation," Survival quoted him as saying. "There are lots of gold miners working illegally in the forest."
Both Survival and the indigenous organizations referred to an attack in 1993 on the Yanomami community of Haximu in Brazil in which they said 16 Indians were killed. Several miners were subsequently convicted for their role in the attack, Survival said.
The organizations called for a criminal investigation into the alleged attack in July, and for measures to clamp down on the illegal activities in the area.
"This is another appalling tragedy for the Yanomami -- heaping crime upon crime," said Stephen Corry, director of Survival. "All Amazonian governments must stop the rampant illegal mining, logging and settlement in indigenous territories."