The death toll from a sudden volcanic eruption in Japan hit 48 today as rescuers discovered 12 new bodies in so-far unexplored areas of the ash-covered peak.

The figure makes the eruption of Mount Ontake, which was packed with hikers when it burst angrily to life on Saturday lunchtime, the worst volcanic disaster in Japan for almost 90 years.

Up until Sunday, 36 bodies had been found, but many of these remained on the ruptured mountain as toxic gas and the risk of further eruptions forced emergency workers to suspend operations.

The grim news of more deaths came after media reports earlier suggested as many as 20 people remained unaccounted for, with an area of the volcano still spewing steam and gas.

Some of the around 1,000 troops, police and fire fighters combing the volcano succeeded today in bringing down 14 more of the bodies that were discovered on Sunday.

An official at Nagano prefecture’s crisis management office said helicopters had brought the dead from the mountain, whose pockmarked lunarscape bears witness to the huge volume of ash and rocks flung from the volcano.

“We believe there are more people still missing, but we don’t know how many they are,” he added.

Broadcaster NHK said earlier in the day rescuers had seen more bodies that they had not yet been able to access.

Hiking is a hugely popular pastime in Japan, with mountain trails promoted by tourism officials who ask walkers to sign in when they begin their trek and sign out again when they finish.

But a local tourism association told the Asahi Shimbun that usually only 10 to 20 per cent of hikers register before entering the mountains in high season.

The report said 327 hikers had registered their presence on Mount Ontake at the time of the eruption.

Rescuers are hoping that many of those who cannot be contacted simply forgot to let mountain managers know they were safe.

Nagano prefecture has posted a notice on its website calling for information on hikers on the list.

However, there exists the grim possibility that many more perished.

“We don’t know if there are people buried deep down under accumulated ash,” a senior police official told the Asahi.

The local fire department said 71 people are missing, while the Nagano prefectural police have received hundreds of reports of people whose whereabouts are unknown, a police spokesman told AFP.

Authorities cautioned that some of these reports would likely have nothing to do with the disaster, which happened without warning during a busy weekend.

Hundreds of people were on the slopes of the volcano as rocks, ash and smoke poured from the fractured crater. Many made it down safely but dozens were trapped on the peak.

Autopsies conducted on the first 12 people whose bodies were retrieved showed they all died from injuries caused by rocks hurled high into the air by the eruption.

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