A “reckless” and “idiotic” American tourist was arrested after illegally visiting the world’s most isolated tribe and leaving behind a can of Coke. Known for killing intruders and firing arrows at helicopters overhead, the Sentinelese tribe on a remote Indian archipelago haven’t had contact with outsiders in decades.

The pre-Neolithic group have been protected from external threats by Indian authorities since 1996, whose navy patrol a five-mile exclusion zone around the island. However 24-year-old Mykhailo Viktorovych Polyakov made an illegal visit to North Sentinel Island on Saturday, which was condemned as “deeply disturbing” by Caroline Pearce, director of indigenous rights group Survival International. She said: “It beggars belief that someone could be that reckless and idiotic. This person’s actions not only endangered his own life, they put the lives of the entire Sentinelese tribe at risk.”

She added: “It’s very well known by now that uncontacted peoples have no immunity to common outside diseases like flu or measles, which could completely wipe them out.”

When Polyakov reached the island, he reportedly blew a whistle to try to attract attention, but after failing to see the tribe, he stepped ashore, left a can of Coca-Cola and a coconut, collected sand samples and recorded a video.

According to police, it isn’t Polyakov’s first offence, having previously attempted illegal interactions with the archipelago’s other indigenous tribes, including Baratang island in January where he illegally filmed members of the Jarawa tribe.

Authorities said it was meticulously planned, having studied sea conditions, tides and access points. They said he arrived in Port Blair, the capital of the Andaman and Nicobar Islands, an Indian territory on March 26.

He then left Kurma Dera beach early on March 29 in an inflatable boat fitted with a motor from a local workshop, and navigated the waters using GPS to reach the territory’s northeastern shore at about 10am.

Local fishermen alerted police when they spotted him returning to Kurma Dera Beach at 7pm.

Police have filed a case against him for breach of protection of aboriginal tribes and informed the ministry of external affairs and the US embassy.

They seized his boat, recovered a GoPro camera containing footage of his activities, and he remains in custody for further questioning.

“We are getting more details about him and his intention to visit the reserved tribal area. We are also trying to find where else he had visited during his stay in the Andaman and Nicobar Islands. We are questioning the hotel staff where he was staying in Port Blair,” a police spokesman said.