Two university students went missing Sunday near the summit of Dainichidake in Toyama Prefecture after an outcropping of snow they were resting on collapsed during their ascent, local police said.
Three members of a rescue team searching for them were also injured when another snow ledge collapsed later in the day, they added.
The pair were identified as Sakuji Naito, 22, of Tokyo Metropolitan University and Kunihide Mizogami, 20, of Kobe University.
The two were part of a 32-member group of university students participating in a mountaineering training program organized by a body affiliated with the Education Ministry, police said.
Four of the other participants were also caught by the collapsing overhang but managed to crawl to safety on their own, rescuers said.
The pair were equipped with radio beacons, and rescuers said they were able to confirm signals from beneath the snow.
However, after the three rescuers were hurt, authorities decided to suspend the search until today because of the dangerous conditions.