Jakarta, Indonesia - A volcano in eastern Indonesia spewed ash and smoke 2 1/2 miles into the sky, forcing the evacuation of hundreds of nearby villagers, officials said Wednesday.

The eruption of Mount Egon on Flores island was caused by magma coming into contact with water, said Surono, a senior government vulcanologist who uses one name.

About 600 residents were evacuated from the village closest to the volcano's crater early Wednesday after clouds of debris shot into the sky, he said, urging that masks be distributed immediately to protect people from breathing the ash.

Indonesia is prone to volcanic eruptions and earthquakes because of its location on the so-called "Ring of Fire," a series of fault lines stretching from the Western Hemisphere through Japan and Southeast Asia.

It has about 100 active volcanoes. The 5,587-foot-high Mount Egon is 1,100 miles east of Jakarta.