Dozens of flights have been cancelled across southern Japan after a volcano erupted for the first time in 22 years.
Mount Aso, located about 625 miles southwest of Tokyo, on Kyushu island, has been blasting out chunks of magma since Friday morning, causing flight cancellations from Kumamoto, the nearest city, and prompting warnings to stay away from its crater.
The volcano has been spewing out lava debris and smoke, shooting plumes of ash a kilometer (3,280 feet) into the sky, The Japan Meteorological Agency said.
Mount Aso is one of the world's largest volcanos, but theobservatory do not expect the eruption to increase in scale.
Eruptions by another volcano, Mount Ontake, on the central Japanese island of Honshu, in September left at least 57 dead, and a further six people remain unaccounted for.
Experts say hikers near the summit might have been hit by rocks flying as fast as 190 miles per hour. Most of the ash fell in the first hour of the explosion, according to the University of Tokyo's Earthquake Research Institute.
Survivors said they fled for their lives as rocks and debris rained down on them while they struggled with hot air and ash hitting their face.
Seismologists have said that increased seismic activity had been detected at Ontake, one of 47 active volcanoes in Japan that are under 24-hour monitoring, but that nothing signaled such a big eruption.
The death toll is the highest from a volcanic eruption in Japan's postwar history, exceeding the 43 people killed in the 1991 eruption of Mount Unzen in southern Japan.
