A rumbling volcano in the central Philippines shot a huge column of ash into the sky on Saturday, prompting the official aviation agency to warn aircraft to stay away, authorities said.
Mount Kanlaon, located on the central island of Negros, launched a plume of whitish-grey ash about 1.5 kilometres (almost a mile) into the air, said Kenn John Veracruz of the official Philippine Institute of Volcanology and Seismology.
The civil aviation office issued an advisory, saying "flights operating in the vicinity of the volcano are advised to avoid flying close to the summit as airborne ash from a sudden eruption can be hazardous to aircraft."
The volcano, located about 510 kilometres south of Manila, has been more active than usual since November, prompting the government to ban hikers from its slopes.
Veracruz said that so far the authorities had not detected any lava rising inside the 2.47-kilometre high volcano but they were checking how far the ash was being scattered by the wind and whether it could affect nearby communities.
"It has been raining in recent days so there was likely water that built up inside the volcano and since the crater is hot, it built up the steam pressure," causing the eruption of ash, Veracruz, a member of the institute's volcano monitoring division, told AFP.
He added that it was possible the volcano could experience another ash eruption.
The civil defence office said they had not received any reports of damage or people affected from the ashfall but that authorities remain on alert.
Kanlaon has had several eruptions, usually of ash, in the past century, leading the government to impose a permanent four-kilometre "danger zone" around the volcano where people are barred from living.
In August, 1996, the volcano abruptly erupted, sending a spray of heated rocks that killed three hikers who were near the summit at the time.
The Philippines is located in the seismically active Pacific "Ring of Fire" and has over 20 active volcanoes.
Earlier this month, Mount Bulusan in the rural eastern province of Sorsogon fired a spectacular column of ash and steam into the air.