Japanese authorities raised the volcanic alert level for Mount Iwate from one to two on Wednesday, warning of potential eruptions and imposing restrictions around the crater.
The Japan Meteorological Agency issued the update at 3 p.m. local time (0600 GMT), citing increased volcanic activity at the volcano, which is located in northern Honshu.
The agency warned that eruptions could affect areas up to two kilometers (1.24 miles) from the Nishi-Iwateyama crater.
"Be on guard for large volcanic rocks that may fly in a ballistic trajectory during an eruption," the agency said. "Follow the instructions of local authorities and avoid risky areas," it added.
Officials also cautioned about the possibility of ashfall and small volcanic rocks being carried by wind to locations downwind of the crater, potentially affecting more distant areas.
The alert level of two advises against approaching the crater. Japan's volcanic alert system ranges from one to five, with five requiring immediate evacuation.
