About 50 police officers began patrolling a mountainous area in Kazuno, Akita Prefecture, on Saturday to prevent bamboo shoot hunters and other people from entering woods where a string of likely bear attacks on humans occurred.

The bodies of four people believed to have been attacked by a bear have been found since late May in the northern Japan area where the victims in their 60s and 70s were searching for edible plants.

The officers set up checkpoints at seven locations on roads leading to the area where the bodies were found.

"The police cannot block everybody who wants to enter the mountains. We hope people will not enter dangerous areas and will protect themselves," said Hajime Takahashi, head of the Kazuno Police Station.

Local hunters killed a 1.3-meter-long Asian female black bear in the area June 10. Human remains and bamboo shoots were found in the animal's stomach, local authorities said.

Takeshi Komatsu, a veterinarian with the municipal government of Kitaakita, a city in the prefecture, said earlier that because the attacks appear to have occurred in a limited area over a short period of time, all four people were likely killed by the same bear.