The number of evacuees fleeing a threatening volcano in North Sulawesi, Indonesia, increased to more than 2,400 on Thursday morning from about 1,000 on Tuesday, an official of National Disaster and Mitigation Management Agency told Xinhua.

A volcanologist at the monitoring post said the 1,750-meter- high Mount Lokon's seismic activity intensified on Thursday, signalling a quite big eruption could happen.

A stadium, three school buildings and one government office building have been used to accomodate growing evacuees, Furqon Sapid Setianto, an official of the agency being stationed in North Sulawesi, told Xinhua by phone.

The agency estimates over 28,000 people living near the volcano may be affected by the eruption.

Farid Ruskan Bina, an official at the post located 5 kilometers from the volcano, said that the volcanic ash went up to 150 to 200 meters high and moved to the north. "The seismic activity of the volcano is still high today, this indicates that there is a possibility of an eruption to happen," he told Xinhua by phone.

Volcanologists raised alert level of Mount Lokon on Sunday evening and delared 3.5 kilometers radius dangerous zone.

Mount Lokon is one of 129 Indonesia's active volcanos, its last explosion was in 1991 which killed one Swiss hiker and displaced thousands of others.