The Philippine Institute of Volcanology and Seismology on 21 August raised the status of Mayon Volcano to Alert Level 1.
The volcano is exhibiting abnormal conditions and has entered a period of unrest, said Philvolcs on its website.
The service institute reminded the public that a 6km Permanent Danger Zone “must be strictly avoided” due to increased chances of sudden steam-driven or phreatic eruption.