STORY: The volcano, which is called Sakurajima and is located on the southern tip of Kyushu near the city of Kagoshima, erupted at about 8:05 pm (1105 GMT), according to the Japanese Meteorological Agency (JMA).
Video footage from JMA's surveillance camera showed what appeared to be a red mass flowing down one side of the volcano, after red projectiles shooting upwards.
Volcanic stones rained down at a distance of 2.5 km (1.5 miles) from the volcano, said JMA. The eruption alert level has been raised to 5, the highest, with some areas advised to evacuate, but no large eruption was expected.
Sakurajima is one of Japan's most active volcanoes and eruptions of varying levels take place on a regular basis. In 2019 it spewed ash 5.5 km (3.4 miles) high.