Indonesia's most active volcano Mount Merapi erupted twice on Monday, spewing hot clouds as far as 1,500 metres, according to the Geological Disaster Technology Research and Development Center.
The center's head Hanik Humaida said the first eruption occurred at 2.03 a.m. for 134 seconds with an amplitude of 40 mm, reports Xinhua news agency.
"The first hot clouds rolled up to 1,300 metres to the southwest," said Humaida.
The second eruption came at 5.11 a.m. for 150 seconds with an amplitude of 48 mm, belching ash clouds as far as 1,500 metres.
Between 12 a.m. to 6 a.m., Merapi also released incandescent lava five times as far as 1,000 metres.
"Currently, the activity of Mount Merapi is still at the third-highest level," added Humaida.
Areas which are potentially dangerous are several rivers where lava and hot clouds are flowing in the south-southwest sector such as the Kuning, Boyong, Bedog, Krasak, Bebeng, and Putih rivers, as well as Gendol river in the southeast sector.
"We urge residents or tourists not to move to these dangerous areas," Humaida said.
Located between the borders of Central Java and Yogyakarta provinces, the volcano's 2010 eruption killed more than 200 people and forced hundreds of thousands to flee their homes.
Indonesia has 127 active volcanoes and about 5 million people within the danger zones.