Darwin, Australia - Huge ash clouds thrown up by an Indonesian volcano have forced airlines to cancel all flights to and from the northern Australian city of Darwin. Mount Sangeang Api began erupting on Friday and plumes of ash have been sweeping south towards Australia. Qantas, Jetstar and Virgin Australia have all cancelled flights. Services between Australia and the province of Bali have also been hit. The authorities say other airports could be affected in the coming days. Hundreds of passengers have been caught up, with disruption expected to continue until at least Sunday. "The volcano is undergoing a sustained, rather significant eruption at the moment," Emile Jansons, manager of the Darwin Volcanic Ash Advisory Centre told Reuters news agency. "For the last 10 hours we've been observing large masses of volcanic ash being generated. "Nobody has a very good handle on what this volcano is likely to do in the next 24 hours or beyond." Volcanic ash can be extremely dangerous to aircraft as the fine particles can damage engines. The cloud is now sweeping south towards as Alice Springs, officials say. Deputy Prime Minister Warren Truss said it could take days for Australian services to return to normal. Indonesia lies across a series of geological fault-lines and is prone to frequent earthquakes and volcanic eruptions. There are about 130 active volcanoes in Indonesia.(FA)