Indonesian volcano rumbles again, spitting massive ash clouds

The Mount Lokon volcano spews thick smoke and 

ash into the air as seen from the town of Tomohon on Sunday.

Jakarta, Indonesia (CNN) -- An Indonesian volcano erupted twice Monday, spewing thick ash clouds a day after the number of evacuees rose to 5,200.

The two eruptions occurred within 10 minutes of one another, spitting ash clouds as high as 600 meters (1,970 feet) into the air.

Mt. Lokon in the northern Sulawesi province first erupted Thursday night. Since then it has erupted several more times.

Authorities worry that the latest eruption sent smoke so high into the sky that it could affect flights at nearby airports.

There were no immediate reports of casualties.

Indonesia is located on the "Ring of Fire," an arc of fault lines circling the Pacific Basin that is prone to frequent earthquakes and volcanic eruptions.