LEGAZPI, Philippines  - The Mayon volcano erupted again Monday, shooting blackish ash and glowing red hot rocks high into the sky and causing many residents to flee to safety in nearby villages, officials said.

There were no immediate reports of casualties in the latest explosion of the roughly 8,100-foot volcano, which began erupting Thursday in Albay province, about 215 miles southeast of Manila.

"In the current eruption period of Mayon, this has been the biggest so far," said Ernesto Corpuz of the Philippine Institute of Volcanology and Seismology. "People should not venture back into the prescribed danger zones."

The volcano belched a column of ash and molten rocks up to four miles high, followed by lightning and continuous rumblings, Corpuz said. Mayon also emitted pyroclastic flows - superheated clouds of volcanic ash that travel up to 50 mph and can instantly incinerate anything in their path.

In Mabinit village, scores of men, women and children ran for their lives, carrying cooking pans, clothes and other belongings after seeing molten rocks and ash hurtling down Mayon's slope, news photographer Nelson Salting said.

More than 47,000 people were evacuated from nearby villages, but some have returned in recent days to check their houses and farms despite warnings by officials.

In nearby Legazpi city, motorists stopped on roadsides to take pictures of the spectacle. Other residents climbed on roofs and yelled and clapped as the volcano erupted.

The repeated explosions indicated that magma is still rising to the dome and that volcanic activity could
continue between two weeks to a month, officials said.

The volcano has been showing signs of unrest since last June, spewing ash-laden smoke high in the sky several times last year, but causing no injuries. An explosion in September forced more than 5,700 people to flee their homes.

Mayon's most violent eruption, on Feb. 1, 1814, killed more than 1,200 people and buried an entire town in volcanic mud flows. An eruption killed more than 70 villagers in February 1993.