The Peruvian government has released a rare video and pictures showing a few never-before-contacted tribal people along the banks of Manu River at Manu National Park in the Peruvian Amazon rainforest.

The footage was taken by tourists who were motor-boating on the river in southeastern Peru, as they captured the lost tribes of the Amazon rainforest preparing to launch an arrow at the boat.

According to National Service for Protected Natural Areas (SERNANP), the state agency responsible for regulating the Protected Natural Areas in Peru, sightings of these indigenous people have been reported by the park ranger staff and tourists in the recent months.

Evidence of sightings suggest the presence of a small population of about 20 people including men, women and children in the area and that they may belong to the Mashco Piro tribe, SERNANP officials said on Monday.

However, the state agency remains clueless about the reason why these people would be often coming along the riverbank in the Amazonian national park, which is a well-known tourist destination.

On Oct. 14, a park ranger was hit by a blunt arrow, which officials believe was a warning signal from the tribes asking outsiders to keep away from their region.

Peru has the third largest number of uncontacted tribal groups in the world, after Brazil and New Guinea. Contact with uncontacted tribes can be fatal for them as they are highly vulnerable to external conditions and not immune to common diseases which can spread through food and clothes that tourists leave for them.

SERNANP has been organizing vaccination programs for local population in a bid to safeguard the physical integrity of indigenous people, and has urged visitors not to seek contact with them either way – in isolation or by leaving objects for them.

The organization has released the first pictures and video of this Peruvian tribe, who were first sighted along Manu riverbanks in May this year. Have a look:

The video depicts tourists panicking and leaving as one of the men from the tribe prepares to attack.