Thousands of villages are being evacuated after a small volcano near the Philippine capital belched a dark plume of steam and ash into the sky in a brief explosion.

Government experts said magmatic materials came into contact with water in the main crater of Taal Volcano in Batangas province, setting off the steam-driven blast.

They said it is unclear if the volcanic unrest could lead to a full-blown eruption.

“It’s just one explosive event, it’s too early to tell,” Renato Solidum of the Philippine Institute of Volcanology and Seismology said at a news conference, adding similar steam-driven explosions may occur.

Philippines Volcano
The blast has led to a heightened risk for nearby villages (Philippine Institute of Volcanology and Seismology – Department of Science and Technology via AP)

The agency raised the alarm at 1,020ft Taal, one of the world’s smallest volcanoes, to the third of a five-step warning system, meaning “magma is near or at the surface, and activity could lead to hazardous eruption in weeks”.

Alert level 5 means a life-threatening eruption that could endanger communities is under way.

Mark Timbal, a spokesman for the government’s disaster response agency, said officials started to pre-emptively evacuate residents from five high-risk villages. Up to 14,000 residents may have to be moved temporarily away from the restive volcano, he said.

Officials reminded people to stay away from a small island in a scenic lake where Taal is located and is considered a permanent danger zone, along with a number of nearby lakeside villages.

Taal erupted in January last year, displacing hundreds of thousands of people and sending clouds of ash to Manila, about 40 miles to the north, where the main airport was temporarily shut down.

The Philippines lies along the Pacific “Ring of Fire,” a region prone to earthquakes and volcanic eruptions.

A long-dormant volcano, Mount Pinatubo, blew its top north of Manila in 1991 in one of the biggest volcanic eruptions of the 20th century, killing hundreds of people.