JAKARTA (XINHUA) - Indonesia's most active volcano Merapi emitted ash clouds three times as far as 3km to the south-east, with ashes spreading to areas in Yogyakarta.

The hot clouds erupted three times at 4.43am local time with an amplitude of 75mm. The first clouds ran for 61 seconds, the second for 131 seconds and the third, 245 seconds.

"A column of smokes was observed as high as 1,000m high above its peak," said head of the Geological Disaster Technology Research and Development Centre Hanik Humaida on Friday (June 25).

At 7.33am local time, Merapi, which straddles Special Region of Yogyakarta and Central Java province, belched more hot clouds as far as 1km to the south-east for 104 seconds, with a column of smokes as high as 600m above its summit.

Based on observations from midnight to 6am, the 2,968m volcano, which is in the status of third-level danger, spewed lava five times to the southwest and six times to the southeast.

The Geological Disaster Technology Research and Development Centre urged people to keep calm, wear masks to avoid dangerous volcanic ash, and close water storage.

Meanwhile, lava flows and ash clouds were estimated to have affected south-southwest areas, such as the Kuning, Boyong, Bedog, Krasak, Bebeng, and Putih rivers.

Merapi has also ejected volcanic materials to areas within a radius of 3km from its peak.