India's threatened Jarawa tribe is facing a new danger from intruders in its jungle home. International attention has previously focused on the danger to the tribe from the daily human safaris that take tourists through the Jarawa's reserve on India's remote Andaman Islands, a phenomenon exposed by the Observer two years ago. But now a rare interview with a member of the tribe has revealed that they are also under attack from their own neighbours on the islands.

In the first public interview since the Jarawa began to make contact with the outside world, a member of the tribe has come forward to protest about the sexual abuse of young women from the tribe by outsiders. The man, whose name is being withheld to protect the identity of those who helped him give his interview, claimed that other Andaman islanders and poachers had started to enter the forest to harass the tribe.

He alleged that the outsiders had introduced alcohol and drugs into the reserve and were sexually abusing girls from the tribe, which numbers about 400 and whose members only started to come out of the jungle 16 years ago.

"The girls say the outside boys press them lots," he said. "They press them using hands and nails, when the girls get angry. They chase them under the influence of alcohol. They fuck the girls. They drink alcohol in the house of girls. They also sleep in Jarawa's house. They chase the girls after smoking marijuana."

The tribesman spoke out days after eight Jarawa girls were allegedly kidnapped by men who landed at Jao Khana in dinghies. Seven men were arrested. That incident followed several other reports of the sexual exploitation of women from the tribe.

The interview is published in the Andaman Chronicle, whose editor, Denis Giles, has campaigned for years to prevent abuse of the Jarawa. He said the man who came out of the jungle did so because he was concerned about the incursions into their territory. And he said the interview showed that the threat to the Jarawa's existence now extended beyond the human safaris that run along the Andaman Trunk Road, which passes through the heart of their reserve. "Until today the world has confined the idea of the exploitation of the Jarawa to the trunk road, but there is another very real exploitation going on in the background," he said

Two years ago India was scandalised after the Observer exposed the human safaris by publishing video footage of girls from the tribe being coerced into dancing semi-naked in return for food. The safaris were condemned around the world and the Indian government promised to take action.

A year later the country's supreme court banned the safaris, only to row back on the decision after the island administration offered assurances that the Jarawa would be protected from the prying gaze of tourists. Hundreds of vehicles still pour through the jungle every day, packed with tourists whose main purpose is to see and try to photograph members of the tribe.

Giles said the trunk road remained the biggest problem facing the tribe. He said the island authorities were stalling on providing an alternative sea route to bypass the Jarawa's jungle, which is supposed to be completed by March 2015. "Andaman administration do not speak about it. They are confident that it will never take place and blame it on official delay," he said.

"But while the road is a major cause of exploitation, the other part is while the authorities were trying to cover up the road issue, they took it easy with exploitation being done by local poachers, in spite of being aware of it."

Poachers, many from Burma, are known to have been regular visitors to the Jarawa's territory, but this is the first public indication of the scale of the interaction with the tribe. Anthropologists and human rights groups have been concerned about the effect on the tribe of contact with outsiders. Disease and the effects of the introduction of alcohol and drugs have been cited as reasons for assisting the tribe in perpetuating its isolation until members are ready for greater contact.

However, other powerful voices on the island have argued for integration, insisting that the Jarawa should be drawn into the mainstream.

The first interview with a member of the tribe was in 2003 with a young man, Enmai, who had broken his leg on a raid on a neighbouring settlement. Since then no one from the tribe has spoken publicly.

The Jarawa is one of the four tribal groups on the islands. The others are the Sentinelese, the Onge and the Great Andamanese (themselves originally consisting of 10 separate tribes).

Sophie Grig, of Survival International, said: "This is shocking first-hand testimony that Jarawa women are being lured with alcohol and drugs and sexually exploited by poachers on their land. These revelations are just the latest example of the Andaman administration's failure to adequately protect the island's most vulnerable citizens.

"Exactly four years ago, the last member of the Bo tribe of the Andaman Islands died. The Bo were one of the 10 Great Andamanese tribes, and were devastated by diseases brought in by the British when they colonised the islands in the 19th century. Many Great Andamanese contracted syphilis after being sexually exploited by the colonisers. Numbering more than 5,000 when the British first arrived, only around 50 of the Great Andamanese still survive today.

"We must ensure that history does not repeat itself and that anyone caught exploiting the Jarawa is prosecuted."