A bear injured four people in Fukushima, Japan, after attacking workers at a car parts factory and later injuring two others at a nearby factory and in a residential area.

One victim suffered serious injuries, while the others were only mildly hurt.

Authorities had not located the bear and believed it may have remained inside the factory.

Japan has seen a sharp rise in bear sightings and attacks, with record numbers reported in recent years as bears emerge hungry from hibernation and expand into human-populated areas, CBS News has reported.

Experts attribute the increase to growing bear populations and rural depopulation, which has allowed bears to extend their range.