Eleven hikers were injured and over 250 others were stranded close to the peak of Mount Ontake, said to be the second-highest volcano in Japan, after it erupted at around 11:53 a.m. on Saturday, various reports said.
Said volcano connects the prefectures of Gifu and Nagano on the island of Honshu.
Of the eleven injured, eight were in serious conditions, including seven who were said to have lost consciousness, said Minoru Kashiwabara, prefecture crisis management official at Nagano, as quoted in the Los Angeles Times report.
The 250 stranded hikers, meanwhile, sought shelter at a lodge close to a summit nearby but was too dangerous to be approached at the moment, and others decided to make their way down as sunset came, Kashiwabara also said.
"It was like thunder! I heard 'boom, boom,' then everything went dark," a woman interviewed by the press said.
Local police authorities in Nagano said four hikers were also believed to have been buried following the eruption of the 10,062-foot 3,067-meter volcano.
Sohei Hanamura of the Nagano prefectural government, however, said in a report that they are still trying to verify reports and are afraid there would be an increase in the number of casualties.
According to a report, police authorities at Nagano have dispatched a team of 80 rescuers to Mount Ontake to assist climbers on their way down.
Kiso Prefectural Hospital was also reported to have sent a medical emergency group.
The Meteorological Agency said further eruptions could be expected and cautioned the public of falling volcanic residue within the four-kilometer radius of the volcano’s crater.
The agency also said that a land ministry camera has observed smoke fluttering down the southern area of the volcano and extending more than three kilometers.
On a 1 to 5 scale, the agency added that the alert level for the mountain has been raised to 3, warning the public to move away from the volcano because ash and debris could reach as far as 2.5 miles away.
Government authorities have ordered necessary measures for rescue operations, gathered reports said.
Prime Minister Shinzo Abe arranged for an emergency task force in Tokyo and to fast track rescuing stranded people.
"Nearly 200 people are in the process of descending the mountain, but we are still trying to figure out details. I instructed to do all we can to rescue the people affected and secure the safety of the trekkers," Abe said as quoted by Reuters.
Aviation officials said flight routes have also been diverted.
Authorities have also restricted any entry to the hiking paths going to the mountain.
Reports said the last major eruption of Mount Ontake was sometime in 1979, emitting more than 200,000 tons of volcanic ash. In 1991, a minor eruption was also experienced, said to have sparked multiple volcanic earthquakes recorded in 2007.
Below is a video taken by one of the hikers during the eruption of Mount Ontake.
