Governor of Yogyakarta here on Thursday called on the residents not to panic, while the nearby Merapi volcano in Central Java province underwent major eruptions in the morning, sending lava and gas clouds close to residential areas.
Governor Sri Hamengkubuwono told a press conference that volcano eruption was predictable and precaution had been taken since June 4, so it was unnecessary for the people around Merapi to panic.
Evacuation in order would be the best choice, he added.
Merapi belched more than 10 times during the period from 06:00 to 10:00 Thursday morning.
Eruption of hot air had lasted for 25 minutes since 07:20 (0020 GMT).
The lava extended four kilometers along the south slope of the mountain.
Meanwhile, thousands of residents in the locality escaped their homes. The villagers in Balerante Village, Kemalang Town, Klaten Regency, which was the nearest living area to Thursday's eruption, fled around.
The volcano is located just north of Yogyakarta province, the scene of the devastating earthquake that killed over 5,800 people on May 27.
Merapi, located between Yogyakarta and Central Java Province, about 450 kilometers southeast of Jakarta, is one of the 65 volcanoes listed as the most dangerous in Indonesia. It has been placed on highest alert since May 13.
Merapi last erupted in 1994, sending out a cloud of searing gas that burned 60 people to death. About 1,300 people were killed when it erupted in 1930.