An alert has been raised over the Philippines' Mayon Volcano amid increased rockfall and sulfuric emissions.

Timelapse footage shows smoke drifting from the volcano in Albay province during heightened 'degassing activity' on June 5. Mayon continued expelling steam-rich plumes until June 6 morning.

PHIVOLCS reported that there have been more frequent rockfalls in the volcano's summit since April 2023.

In a June 6 bulletin, the agency said it had recorded 74 rockfall events in the past 24 hours, each lasting one to four minutes.

PHIVOLCS warned in a statement: 'The public is reminded that there is current unrest driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruptions.

'Entry into the six-kilometer-radius permanent danger zone must be strictly prohibited to minimize risks from sudden explosions, rockfalls, and landslides. In case of ash fall events that may affect communities downwind of Mayon's crater, people should cover their nose and mouth with a damp, clean cloth, or dust mask.'

Experts said a major explosion was 'unlikely' despite the increased seismic activity.

Dr. Paul Alanis, a volcanologist of PHIVOLCS - Bicol Region, told local media: 'Right now, the scenario of a major eruption is quite remote. But of course, there is still a possibility of small eruptions.'

The Civil Aviation Authority of the Philippines has barred planes from flying too close to the volcano.

An Alert Level 2 indicating 'moderate levels of volcanic unrest' has been hoisted over Mayon Volcano. Residents have been warned to be vigilant of sudden steam-driven eruptions, rockfalls, and lahar during heavy rain.

Meanwhile, the Philippines' Taal Volcano in Batangas province was placed on Alert Level 1 with a 'low level of volcanic unrest' after it blasted smoke plumes up to 3,000 feet high over the weekend.