Thirty one hikers feared dead in sudden volcano horror blast
Thirty one people are presumed dead near the peak of a Japanese volcano that erupted a day earlier, catching hundreds of hikers unawares.
The deaths on Mount Ontake, 200km west of Tokyo, were the first from a Japanese volcanic eruption since 1991.
Police said the 31 were found in "cardio-pulmonary arrest", but declined to confirm their deaths pending a formal examination, as per Japanese custom.
An official in the area said rescue efforts had been called off due to rising levels of toxic gas near the peak, as well as approaching nightfall.
Hundreds of people, including children, were stranded on the mountain, a popular hiking site, after it erupted without warning on Saturday, sending ash pouring down the slope for more than 3km.
Most made their way down later on Saturday but about 40 spent the night near the 3,067 metre peak.
"The roof on the mountain lodge was destroyed by falling rock, so we had to take refuge below the building," one told NHK national television.
More than 40 people were injured, several with broken bones.
Earlier, the Fire and Disaster Management Agency had said authorities were trying to confirm the whereabouts of 45 people. It was not clear whether those 45 included the 31 people found in cardio-pulmonary arrest.
The volcano was still erupting last night. Ash was found on cars as far as 80km away.
Volcanoes erupt periodically in Japan, one of the world's most seismically active nations.
Ontake, Japan's second-highest volcano, last erupted seven years ago.
Satoshi Saito, a 52-year-old hiker who descended less than an hour before the eruption, said the weather was good and the mountain, known for its autumn foliage, was crowded with people carrying cameras.
"There were no earthquakes or strange smells on the mountain when I was there," Saito, who usually climbs Ontake several times a year, said. He also said there were no warnings of possible eruptions posted on the trail.
Video footage shows huge grey clouds tumbling towards climbers at the peak and people scrambling to descend as blackness enveloped them. NHK footage showed windows in a mountain lodge darkening and people screaming as heavy objects pelted the roof.
"All of a sudden ash piled up so quickly that we couldn't even open the door," Shuichi Mukai, who worked in a mountain lodge just below the peak, said. The building quickly filled with hikers taking refuge.