A volcano in eastern Indonesia spewed hot lava and clouds of ash high into the air early Monday, a vulcanologist said, hours after hundreds of villagers living on its rumbling slopes were evacuated.

There were no reports of injuries or damage, said Yudi Satipang, a vulcanologist who has been monitoring Mount Karangetang on Siau island since it was placed on high alert over the weekend.

"It sounds like huge thunderclaps," he said of the booming gas blasts from the crater, adding that villages, farms and trees on the 5,577-foot -tall mountain were covered in thick gray ash.

Karangetang is one of Indonesia's most active mountains, and it has been rumbling for days.

Nearly 600 residents living within the danger zone have fled to safety, and many were seeking shelter in government buildings, schools and mosques.

Indonesia, the world's largest archipelago, is prone to seismic upheaval due to its location on the so-called Pacific "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin.

Siau, a popular diving island, is part of the Sulawesi island chain. It lies some 1,444 miles northeast of the country's capital, Jakarta.