(JAKARTA, Indonesia) — Indonesian authorities raised the alert for the volatile Mount Merapi volcano on the densely populated island of Java and ordered people within 3 kilometers (2 miles) to evacuate. Merapi has erupted four times since Monday, sending out a 3,500 meter (11,483 feet) column of volcanic material and dusting the surrounding region in ash. Sutopo Purwo Nugroho, the national disaster mitigation agency’s spokesman, said some 660 people living within the exclusion zone have evacuated since early Tuesday. Indonesia’s geological agency raised Merapi’s alert from normal to “beware,” because of its increased activity. There have been no reports of casualties and operations at Adi Sucipto airport in Yogyakarta have not been affected. Citizens are seen affected by volcanic ash when Mount Merapi erupts in Yogyakarta, Indonesia. " data-medium-file="https://timedotcom.files.wordpress.com/2018/05/gettyimages-957290670.jpg?quality=85&w=300" data-large-file="https://timedotcom.files.wordpress.com/2018/05/gettyimages-957290670.jpg?quality=85&w=600" class=" wp-image-5286605" src="https://timedotcom.files.wordpress.com/2018/05/gettyimages-957290670.jpg?w=300&quality=85&w=472" alt="Mount Merapi Eruption In Indonesia" width="472" height="321"> Riau Images/Barcroft Media/Getty Images Citizens are seen affected by volcanic ash when Mount Merapi erupts in Yogyakarta, Indonesia. The 2,968-meter (9,737-foot) mountain is about 30 kilometers (18 miles) from the Yogyakarta city center.