Thousands of people were urged to evacuate their homes late on Thursday after a volcano erupted south of Manila and sent sent steam and rock fragments hundreds of metres into the sky.
Taal volcano, which sits in a picturesque lake within another volcano, has been belching sulphur dioxide for several days, creating a thick haze over the capital and several surrounding provinces, prompting health warnings.
The previous eruption, in January 2020, shot ash 15 kilometres into the air and spewed red-hot lava, crushing scores of homes, killing livestock and forcing more than 135,000 people into shelters.
Taal burst to life again on Thursday afternoon with a "short-lived, dark phreatomagmatic plume" that rose a kilometre into the air, the Philippine Institute of Volcanology and Seismology said.
That was followed by "four short phreatomagmatic bursts" that produced 200-metre plumes above the main crater lake, the institute said in a later update.
The agency warned of "ongoing magmatic extrusion at the main crater that may further drive succeeding explosions", as it raised the alert level from two to three.
It "strongly recommends" the evacuation of the volcano island and "high-risk" areas of Agoncillo and Laurel towns.
"We're just raising the alert because something is happening and it can lead to a higher activity," said Renato Solidum, head of the agency.
Mariton Bornas, head of the agency's volcano monitoring division, said that, so far, they "don't expect the same scenario" as last year's eruption.
A spokesman for the national disaster agency said its local agents had called an emergency meeting with government officials and emergency services. He estimated nearly 15,000 people were living in the most vulnerable areas.
Agoncillo disaster officer Junfrance De Villa said preparations were under way in case residents needed to be moved from the lakeside community.
"Some have already taken shelter with relatives," Mr De Villa said.
The Philippine Red Cross tweeted late on Thursday that its volunteers had driven some residents from an area of Laurel to a primary school being used as an emergency shelter.
The Philippine Coast Guard said on Facebook that two of its vehicles were sent to Laurel to assist families wanting to leave their homes.
Taal is one of the most active volcanoes in a nation hit periodically by eruptions and earthquakes due to its location on the Pacific "Ring of Fire" – a zone of intense seismic activity.
Access to the volcano island, which was once home to a community of thousands, has been prohibited since last year.