next Image 1 of 2

prev Image 2 of 2

The Philippines' most active volcano has exploded thunderously and authorities warn a hazardous eruption is possible within days.

Renato Solidum of the Philippines Institute of Seismology and Volcanology and other officials said Mount Mayon ejected a huge column of volcanic fragments, ash and steam into the sky around noon Monday, shrouding nearby villages in darkness.

Authorities raised the alert level to four on a scale of five, which means an explosive eruption is possible within days.

Mayon has been acting up for more than a week, causing more than 27,000 villagers to flee to safety.