Indonesia's most volatile volcano is erupting, spewing plumes of hot ash and hurling rocks into the air. Officials said Merapi, in central Java, began erupting just before dusk on Tuesday. Scientists warn the pressure building up beneath its lava dome could lead to one of the most powerful blasts in years. Thousands of residents living on the volcano's slopes have been evacuated. Officials said a further 13,000 people, however, need to be evacuated from within a 10-mile radius of the volcano. Television footage showed thousands of people fleeing the area, some covered in white ash. On Monday, officials monitoring the volcano raised the alert for Mount Merapi to the highest possible level. Since then, more than 600 volcanic earthquakes have been recorded around the mountain.