Philippines volcano Mount Bulusan erupted on Monday morning at 9:15 a.m. local time, per the ABS-CBN News Channel.
Ash and steam from the explosion reached as high as 2 kilometers, according to the report.
The Philippine Daily Inquirer posted this photo of the Mount Bulusan eruption to Posterous.
Journalist Harold Geronimo of Manila, Philippines, was the first to report the eruption on Twitter, sending this tweet from his Blackberry minutes after the eruption.
UPDATE: The Philippine Institute of Volcanology and Seismology confirmed the ash explosion and says it was caused by steam buildup. The institute advises all aircraft to avoid the vicinity and warns that the ash emission could trigger respiratory illnesses for those near the volcano. People are advised not to enter the 4-kilometer danger zone around Mount Bulusan.