Indonesia's most active volcano, Mount Merapi, erupted early Friday, spewing sand and pyroclastic material and sending an ash column as high as 18,045 feet into the sky.
It was not clear how many residents living around Merapi had left for local shelters, but around 12,000 people live in its immediate vicinity.
Mount Merapi in Central Java experienced what officials call a phreatic eruption, which is a phenomenon caused by the heating and expansion of groundwater.
"Volcanic ash rain were found in Kaliurang, Yogyakarta".
The danger zone has been restricted to a 3km radius from the peak of Mount Merapi. Several flights into the city were cancelled.
The Adisutjipto International Airport was closed at about 10.42am (11.42am Singapore time) and reopened at 2.17pm, state air-navigation operator AirNav Indonesia said. "AirAsia strongly encourages all guests to update their contact details at airasia.com to ensure that they are notified of any updates to their flights".
"If you're in the area, you should monitor local media, exercise caution and follow the advice of local authorities". "The lava tour outside is also under our observation".
Merapi previously erupted in 2010, killing more than 300 people and forcing 280,000 to flee, in what is considered its most powerful eruption since 1930.
It was the first eruption of the volcano since 1963, in which 1,100 people were killed.