The Philippines raised the alert at its restive Mayon volcano by one notch early today, citing signs of rising magma that could lead to hazardous eruptions. <br/><br/>Residents were evacuated from two villages near the volcano, in central Albay province, following a "phreatic or steam-driven eruption" yesterday. <br/><br/>The Philippine Institute of Volcanology and Seismology (Phivolcs) said in its latest bulletin that the explosion unleashed ash, rocks and sulfuric odor, and was followed by rumbling sounds and a faint glow in the crater. <br/><br/>Phivolcs raised the alert to Level 2, which means that the current activity could lead to more phreatic eruptions or eventually to hazardous magmatic eruptions. <br/><br/>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.