The volcano, located in the Albay province of central Philippines, first spewed ash on Saturday afternoon – followed by a further five-minute eruption on Sunday morning.
Since the eruptions, a “faint crater glow” has been observed, and dramatic images sent in to Express.co.uk show a bright red light being emitted from the mountain.
The incredible photographs show the glowing red lava at the peak of the 2,463 metre mountain just hours after the volcano erupted for a second time.
The Philippine Institute of Volcanology and Seismology (Phivolcs) raised the alert to level 2 in the early hours of Sunday, which means that the current activity is “probably of magmatic origin, which could lead to more phreatic eruptions or eventually to hazardous magmatic eruptions.”
A phreatic eruption, also known as a phreatic explosion, occurs when magma heats ground or surface water, resulting in steam rising into the sky.
And just a few hours later, the threat was raised again from two to three as Phivolcs warned of “hazardous eruption” within weeks or days as Mayon Volcano has exhibited “high unrest” and its magma is at the crater.
Under Alert Level 3, the extension of danger zone in the sector where the crater rim is low will be considered.
Phivolcs said: “For the past 24 hours, Mayon Volcano in Albay province has noticeably increased its unrest.
“After three phreatic eruptions and 158 rockfall events between 4:21 p.m. (January 13) and 7:25 p.m. (January 14), Mayon’s summit crater is now exhibiting bright crater glow that signifies the growth of a new lava dome and beginnings of lava flow towards the southern slopes.
“In view thereof, PHIVOLCS-DOST is now raising the alert status of Mayon Volcano from Alert Level 2 to Alert Level 3
Mayon’s most destructive eruption was in February 1841, when lava flows buried a town and killed 1,200 people. It last erupted in 2014, spewing lava and forcing thousands of people to evacuate.