Tokyo, Sep 27 (IANS): Japan on Sunday held a memorial to mark the eruption of Mount Ontake, the country's worst volcanic disaster in 70 years.

The volcano erupted on September 27, 2014, claiming the lives of 58 people, and five people remain unaccounted for, NHK news agency reported.

The memorial was held in Otaki village in Nagano prefecture.

Bereaved families, police and firefighters offered prayers at 11.52 a.m., the exact time of the eruption.

In June of this year, authorities lowered the alert at Mount Ontake to level 2 on a scale of 5. This led to the easing of entry restrictions in September, partially reopening hiking routes and allowing climbers to go up to the 2,800-metre point on the over 3,000 metre-high mountain.

The eruption prompted efforts to ensure the safety of residents and climbers.

A town at the foot of the mountain introduced a new system to send out volcanic information to climbers' smartphones.

Japan's Meteorological Agency boosted monitoring by setting up new observation points around the mountain.