Evacuations are underway in the Philippines as the country's most active volcano is showing strong sings of an eruption.

According to the Associated Press, Mount Mayon has already sent lava fragments rolling about half of a mile down its slope. The Philippine Institute of Volcanology and Seismology (PIVS) raised the alert level for the volcano and warned a severe eruption could happen within weeks.

"It's already erupting, but not explosive," Renato Solidum, the PIVS' chief, told the AP. "Currently, the activity is just lava coming down. If there is an explosion, all sides of the volcano are threatened."

Ed Laguerta, a volcanologist, said he noticed the lava fragments late Monday when some thick clouds cleared his view of Mount Mayon's summit. He could see the lava rolling down the slope from a distance of seven miles.

Mount Mayon is known its pristine cone-shaped appearance and is a tourist attraction for the Albay Province, some 200 miles southeast of Manila, as such.

Albay Gov. Joey Salceda issued a mandatory evacuation for anyone whose residence is within six kilometers of the volcano, but the order encompassed about 12,000 citizens within eight kilometers of Mount Mayon.

Cedric Daep, an Albay safety officer, told the AP "thousands have been evacuated since last night."

The current warning level the PIVS has is also classified as "critical," which the third-highest possible level, according to CNN. The agency said, "Mayon is exhibiting relatively high unrest and that magma is at the crater and that hazardous eruption is possible within weeks."

"This will boost local tourism... it's like a party, people are out at night watching," Marti Calleja, a member of the Philippines' tourism industry, told AFP. "It's dramatic, like a fireworks show... when there's nothing happening (in the volcano) it's all dark around here, but now it's picture-perfect."