A volcano in the central Philippines spewed ash early Tuesday, blanketing fields and villages as far as three miles away, but there was no immediate sign of a major eruption, scientists said.

The 5,150-foot Mount Bulusan volcano has been showing signs of unrest with on-and-off ash and steam explosions since March 2006.

"We are keeping an eye on some villages in Juban and Irosin town. An ash explosion can occur there anytime," said Bella Tubianosa from the Philippine Institute of Volcanology and Seismology.

She said the latest burst sent ash falling three miles west of the volcano, which is about 240 miles southeast of Manila.

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Television reports said the ash column caused panic in the surrounding area, with residents running out of their homes.

Villagers have been warned not to venture into a 2.5-mile "permanent danger zone" around the volcano. Broadcaster ABS-CBN said the military was expected to enforce an evacuation of people from Bulusan's immediate vicinity.

The Philippine archipelago lies on the Pacific Ocean's "Ring of Fire," where volcanic activity and earthquakes are common.

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