More than 19,000 people have fled their homes in western Indonesia's Sumatra following a series of volcanic eruptions in Mt Sinabung.
A total of nine successive eruptions rocked the island, spewing lava and clouds of gas as high as 7,000m (23,000 ft) into the sky.
The volcano threw up hot rocks and ash into the air, triggering panic in the province, even though no casualties were reported.
Sutopo Purwo Nugroho, National Disaster Mitigation Agency spokesman, said that an area of 5 km (3 miles) around the volcano has been sealed and declared a danger zone, and people are being evacuated from villages in the zone to temporary shelters.
"On Monday night, 19,126 people had fled their homes, and we expect that number to rise," Nugroho said.
Police and soldiers were also evacuating people who had voluntarily stayed behind in the danger zone, he said.
The volcano came to life in September after being dormant for three years and has erupted sporadically since then.
The alert status for Mt Sinabung was raised to the highest level in November when it erupted multiple times, forcing about 18,000 people to flee the area.
"Mount Sinabung remains on the highest alert level and we have warned there should be no human activity within a five-kilometre radius of the crater," said Nugroho.
AP reported that gray ash from the eruption spread far and wide up to 70 km (43 miles) southeast of the mountain, inundating scores of villages in debris.
Air traffic around the mountain has been closed, said Bambang Ervan, spokesman for the transportation ministry.
Volcanic Activity in Indonesia
Indonesia has about 130 active volcanoes and lies on a major tectonic fault line, which is on the subduction zone between the Eurasian and the Indo-Australian plate. The zone is a part of the "Pacific Ring of Fire", an arc of volcanoes and fault lines spanning about 40,000 km across the Pacific.
Mt Sinabung had been dormant for the last four centuries, but unexpectedly erupted in 2010 killing two people and displacing over 30,000 inhabitants.
Scientists have linked renewed volcanic activity in Indonesia to the tsunami, as there have been several eruptions in Indonesia in last three years since the great deluge, claiming hundreds of lives and frequently forcing mass evacuations.