By Rachel Harvey
BBC News, Jakarta
Molten lava has begun flowing from a volcano on the Indonesian island of Java which has been showing increased signs of activity over recent weeks.
There has still not been a mass evacuation of villagers
Scientists are warning that Mount Merapi is likely to erupt, but say they cannot predict the exact timing.
The area around the volcano has been on official alert for at least two weeks.
Despite the latest developments, the threat level has not yet been raised to the highest alert - a move which would trigger a mass evacuation.
The scientists monitoring Mt Merapi's rumbling have been on the lookout for specific signs, including flows of lava and evidence of burning around the crater.
Both have now been confirmed, suggesting the pressure within the volcano is reaching a critical point.
There is now a growing consensus that an eruption is imminent - but no one can say precisely when or how powerful it is likely to be.
Thousands of people, mostly the elderly and mothers with young children, have already evacuated their homes on Mt Merapi's fertile slopes.
Emergency shelters have been set up away from the danger zone, but some reports suggest that supplies of food and sanitation facilities are inadequate.
Thousands more people are staying put for now, reluctant to leave their belongings and livestock behind.
But if the volcano's pyrotechnics become more threatening still, they may yet be forced to go.