"They described being attacked by non-native people and many died after coming down with the flu and diphtheria," said interpreter Jaminawa Jose Correia, according to a report on the G1 web portal and cited by AFP.
Several of the tribal people have been treated for flu, which could be especially deadly as they have no immunity to the disease.
“At first they were afraid and wary, but thankfully in the end they understood, believed us, trusted the medical team and accepted the medicine,” Carlos Travassos of Brazil's National Indian Foundation (FUNAI) told Forbes. “It was a difficult and slow dialogue.”
Travassos added that "the group told us their tribe had been shot at by white men."
While it's not yet clear who has been shooting at them, advocates believe it was loggers and drug traffickers in Peru who have been moving into tribal lands, causing indigenous peoples to flee.
"If you're a non-contracted tribe who has some knowledge but very little knowledge of that world out there and what you see is people coming in, stealing your resources, scaring off the game that you rely on for food and most dangerously wielding firearms -- this must be an incredibly frightening experience," Fiona Watson of Survival International told NPR.
Survival International advocates on behalf of uncontacted tribes and works with FUNAI.
"This news could hardly be more worrying -– not only have these people confirmed they suffered violent attacks from outsiders in Peru, but they have apparently already caught flu," Survival International director Stephen Corry said in a news release. "The nightmare scenario is that they return to their former villages carrying flu with them."