SAPPORO (Kyodo) Ten climbers have died on two mountains in the Taisetsu mountain range in central Hokkaido since Thursday, many of them succumbing to hypothermia in bad weather, police said Friday.

At least six of the 10 were found to have died of hypothermia and two other climbers were also hospitalized for mild hypothermia that is not life-threatening, as weather conditions around the range were unstable Thursday with strong wind and rain, the police and local meteorological observatory said.

There are few mountain lodges in the area, and the victims are believed to have exhausted themselves in the poor weather, prompting the police to investigate the possibility that climbing tour operators and guides were professionally negligent, resulting in the deaths.