An American man killed with arrows by an isolated Indian island tribe may have been trying to convert the remote islanders to Christianity.

Dependera Pathak, director-general of police on India’s Andaman and Nicobar Islands, said seven fishermen have been arrested for helping the American visit North Sentinel Island, where the killing occurred.

Visits to the island are heavily restricted by the government. The tribes people have previously fired arrows at unwelcome visitors.

Pathak identified the American as John Allen Chau and said he earlier described himself at a hotel as 26-year-old and from Alabama.

John Allen Chau was apparently killed by arrows on the remote island. (Instagram)

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He was apparently killed by arrows, but the cause of death can’t be confirmed until his body is recovered.

Reuters is reporting Chau was attempting to convert the tribes people to Christianity.

A source with access to handwritten notes that Chau gave to the fishermen to pass on to a friend said that Chau described his efforts to spread Christian beliefs.

The source, who asked not to be named, said Chau wrote that he was “doing this to establish the kingdom of Jesus on the island … Do not blame the natives if I am killed.”

Tribespeople on the Sentinel Islands are known to attack outsiders with a bow and arrow. (AAP)

The Sentinelese people on the small forested island are known to resist contacts with outsiders, often attacking anyone who comes near.

The Andaman and Nicobar Islands are a group of islands at the juncture of the Bay of Bengal and Andaman Sea.

Police have approached anthropologists with contacts on the island in an effort to visit and recover the body, Pathak said.

He said Chau arrived in the region on October 16 and stayed in a hotel while he prepared to visit the prohibited island. He had earlier visited the Andaman and Nicobar Islands in 2015 and 2016, Pathak said.

American adventurer John Allen Chau. (Instagram)

He said Chau organised his visit to the island through a friend who hired seven fishermen to take him there on a boat, which also towed his kayak.

Chau went ashore in his kayak on November. 15 and sent the boat with the fishermen out to sea to avoid detection, Pathak said.

He interacted with some of the tribespeople, giving them gifts he had prepared such as a football and fish.

But the tribespeople became angry and shot an arrow at him which apparently hit a book he was carrying, Pathak said.

North Sentinel Island remains isolated from the outside world. (AAP)

The American’s kayak became damaged, so he swam to the fishermen’s boat, which was waiting at a prearranged location.

There he spent the night and wrote out his experiences on pages of paper which he gave to the fishermen, Pathak said. He set out again to meet the tribes people on November 16.

The US consulate in Chennai, the capital of southern Tamil Nadu state, was aware of the reports concerning an American in the islands, but spokeswoman Kathleen Hosie declined to comment further due to privacy considerations.

Shiv Viswanathan, a social scientist and a professor at Jindal Global Law School, said the North Sentinel Island was a protected area and not open to tourists.

"The exact population of the tribe is not known, but it is declining. The government has to protect them."

Poachers are known to fish illegally in the waters around the island, catching turtles and diving for lobsters and sea cucumbers.

Tribespeople killed two Indian fishermen in 2006 when their boat broke loose and drifted onto the shore.