"People must empty and avoid any activity within a 3-kilometer radius of Merapi’s peak," Humaida said as quoted by The Jakarta Post newspaper.
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According to the publication, the Volcanology and Geological Disaster Mitigation Center (PVMBG) has raised the alert status of Mount Merapi from normal to caution, the third-highest level.
Other media reports indicate that since Monday, Merapi has erupted four times and sent out an 11,483-feet column of volcanic material into the air.
Merapi volcano, located 18.6 miles from the city of Yogyakarta and more than 320 miles from the capital of Indonesia, Jakarta, is one of the most active volcanoes in the country. Large eruptions are observed every seven years, while small ones are registered about two times a year.