Police say it's been determined that almost all of the people killed on a Japanese volcano died of injuries from being hit by volcanic rocks that flew out during its eruption.

Rescuers have retrieved 47 bodies from the ash-covered summit area of Mount Ontake since Saturday's eruption.

Nagano prefectural police said Thursday that doctors concluded that all but one of the bodies showed signs of having been hit by volcanic boulders and rocks. They said the other victim died of burns from inhaling hot air.

Most of the bodies were found near the summit, where many climbers were resting or having lunch. The search for more bodies continued Thursday, but ended early due to bad weather.

Authorities continued to look into the possibility that about 20 people were still missing.