JAKARTA - INDONESIA has raised the alert level of one of the most active volcanoes on Java, a volcanology official said on Thursday.

The volcanology agency in Bandung raised the alert on Semeru mountain near Malang in East Java late on Wednesday after it shot out some 500 to 800 degree Celsius clouds, the official said.

'The heat clouds slid three kilometres from the crater but no evacuation is needed because people live quite far from the crater,' Surono, head of the agency, said.

People have been told to stay at least four kilometres from the 3,676m high mountain, which is also popular among hikers. Seven people were killed from the mountain's heat clouds in 1994.

The volcanic dust from Semeru has not yet disturbed flights in the nearest town of Surabaya because it is only 600m from the mountain's top.

Mt. Semeru is the highest mountain on Java and one of the highest in Indonesia. It is also one of the most active volcanoes in Indonesia, belching clouds and steam just about every day.

Indonesia has the nighest number of active volcanoes of any country, sitting on a belt of intense seismic activity known as the 'Pacific Ring of Fire'.

People often live and farm on the slopes of volcanoes because of the rich volcanic soil. -- REUTERS