Philippine's government evacuated thousands of residents from the danger zone of Mayon volcano in Albay province some 330 km southeast of Manila.
The Philippines Earthquakes Institute said that a flare had been observed above the volcano muzzle as tremors and rock fallout increased in frequency.
The German news agency said that the Institute has raised the alert level to the third degree as tremors increased from 32 to 45 and rock fallout from 79 to 270 over the past 24 hours.
The Institute anticipated that the volcanic eruption could happen anytime this week.