A volcano in the Albay province of the Philippines erupted Sunday, leading to the evacuation of around 13,000 people in the surrounding area.

Mayon Volcano, the Philippines’ most active volcano, is spewing lava in what The Associated Press called a “gentle eruption” that could turn violent.

The Philippine Institute of Volcanology and Seismology issued an alert level three out of five, warning that a “hazardous eruption is possible within weeks or even days.”

The institute also recommended that everyone within a 6-kilometer radius of the crater be evacuated. So far, around 13,000 people, or 88% of residents, have evacuated the area, the Philippine Provincial Information Office said, per CNN. However, some residents have not been evacuated from the Permanent Danger Zone.

Related
A Hawaiian volcano is erupting. See videos of the eruption

Institute director Teresito Bacolcol told CNN Philippines that the alert level may rise to a four if they see an increase in volcanic earthquakes.

Currently the lava flows are “slow moving” after an effusive eruption began Sunday night, Bacolcol said.

“Effusive eruptions are generally less violent and produce less ash and volcanic gases than explosive eruptions,” he stated.

A video from CNN Philippines shows the effusive eruption as lava flows down the side of the volcano.

Mayon previously erupted in 2018, “displacing tens of thousands of villagers,” according to AP.