Updated at 3:35 p.m. ET
Mount Aso — a volcano on Japan's southern main island of Kyushu — has erupted, spewing black smoke and ash more than a mile into the air, the Japanese Meteorological Agency says.
So far, there have been no reports of injuries or damage, but ash fell as far as 2.5 miles from the crater.
Mount Aso, which stands 5,222 feet high, is the country's largest active volcano.
Reuters reports that it also happens to be a popular hiking spot: "There were a handful of people at a parking lot near the peak but they were being evacuated safely, officials said on Monday. They said the eruption had come without warning."