Red-hot lava has started gushing out of a volcano in the Philippines prompting authorities to warn of "an imminent hazardous eruption".
The Taal Volcano in Batangas province, south of the capital Manila, began to erupt in the early hours of Monday after blasting steam and rock up to 15,000 metres into the air on Sunday.
Tens of thousands of people have fled the area near the volcano through heavy ash and tremors.
Experts warned that the eruption could get worse and plans are being made to evacuate hundreds of thousands more.
So far, there have been no reports of injuries or damage.
A truck, however, skidded out of control and fell on its side on an ash-blanketed road, killing the driver and injuring three companions in southern Laguna province.
Police said his death may be linked to slippery road conditions.
Clouds of ash blew more than 62 miles (100km) north, reaching Manila on Sunday, and forcing the partial shutdown of the country's main airport with more than 500 flights cancelled.
Manila International Airport was operating some flights on Monday, authorities said.
President Rodrigo Duterte's aircraft was able to land in Manila on Monday from his southern home city Davao, his spokesman said, adding he saw the extent of the volcanic devastation from the plane.
An alternative airport north of Manila at Clark freeport remains open but authorities said it would shut it down too if ashfall threatens flights.
The government's disaster response agency and other officials reported more than 30,000 villagers have fled their homes in the hard-hit province of Batangas and nearby Cavite province, but officials expect the number to swell with hundreds of thousands more moving out of harm's way.
Some residents could not move out of ash-blanketed villages immediately due to a lack of transport and poor visibility.
Others refused to leave their homes and farms.
Wilson Maralit, mayor of Balete town in Batangas, told DZMM radio: "We have a problem - our people are panicking due to the volcano because they want to save their livelihood, their pigs and herds of cows.
"We're trying to stop them from returning and warning that the volcano can explode again anytime and hit them."
Mr Maralit, whose town lies along the shoreline of Taal Lake surrounding the erupting volcano, appealed for troops and more policemen to stop distraught residents from sneaking back to their high-risk villages.
Coastal communities around the lake have also been told by officials to evacuate to safer areas in case an eruption causes a tsunami or pyroclastic surge.
Residents have been urged "to take precautionary measures and be vigilant of possible lake water disturbances related to the ongoing unrest".
Renelyn Bautista, a 38-year-old housewife who fled from Laurel town with her two children by hitching a ride to safety, said: "The air turned muddy because of the ashfall and it started to smell like gunpowder".
The Philippine Institute of Volcanology and Seismology raised the threat level from 3 to 4, meaning a hazardous eruption is imminent.
A statement said: "Hazardous explosive eruption is possible within hours to days. (The institute) strongly reiterates total evacuation of Taal Volcano Island and additional evacuation of areas at high risk... within a 14km radius."
As tremors shook the area, volcanic lightning flickered in the column of steam and ash.
Pictures from the scene showed the sky darkened by the ash plume and a thick layer of dust covering everything in the nearby town of Talisay.
Ashfall has been reported in towns and cities several miles away, with families advised to stay indoors and don masks and goggles for safety.
Authorities recorded a series of earthquakes and motorists are also being hampered by poor visibility due to the ashfall.
Taal, one of the smallest volcanos in the world, is among two dozen active cones in the Philippines, which lies along the so-called Pacific 'ring of fire'.