Several airlines have temporarily suspended flights between Singapore and Jakarta because of volcanic ash spewing from Mount Merapi in central Java.
Among those affected were Singapore Airlines, Japan Airlines, Malaysia Airlines, Lufthansa and Cathay Pacific.
Merapi, one of the world's most active volcanoes, began erupting two weeks ago and has killed more than 130 people.
Airline officials say the ash is a safety threat and could damage aircraft.
Domestic flights have been unaffected.
Azharuddin Osman, director of operations for Malaysia Airlines, said "the volcanic ash presence in the airways surrounding Jakarta could cause severe damage to our aircraft and engines, which could impair the safety of our operations."
Indonesia has already been forced to close its international airport at Yogyakarta and divert flights to the nearby city of Solo. A Silkair flight to Solo was also cancelled.
Mount Merapi has been producing thick clouds of ash and superheated gases in its biggest eruption in a century. In addition to the loss of life, some 200,000 people have been evacuated from the area.
Among those affected were Singapore Airlines, Japan Airlines, Malaysia Airlines, Lufthansa and Cathay Pacific.
Merapi, one of the world's most active volcanoes, began erupting two weeks ago and has killed more than 130 people.
Airline officials say the ash is a safety threat and could damage aircraft.
Domestic flights have been unaffected.
Azharuddin Osman, director of operations for Malaysia Airlines, said "the volcanic ash presence in the airways surrounding Jakarta could cause severe damage to our aircraft and engines, which could impair the safety of our operations."
Indonesia has already been forced to close its international airport at Yogyakarta and divert flights to the nearby city of Solo. A Silkair flight to Solo was also cancelled.
Mount Merapi has been producing thick clouds of ash and superheated gases in its biggest eruption in a century. In addition to the loss of life, some 200,000 people have been evacuated from the area.