Tens of thousands continued fleeing to an uncertain future yesterday, amid fears of a bigger and more dangerous eruption at the Taal volcano south of Manila.

At least three towns were declared "no-go zones" because of their proximity to the volcano.

The towns were placed on lockdown yesterday, to prevent inhabitants, wanting to care for their livestock and fearful of thieves, from attempting to sneak back to their homes.

The National Disaster Risk Reduction and Management Council said more than 35,000 people had been evacuated.

The number could still swell, as the Philippine Institute of Volcanology and Seismology (Phivolcs) warned that a "hazardous, powerful eruption" was still on the cards.

The 14km "danger zone" declared around Taal covers a population of some 460,000.

Taal spurted fountains of steam and red-hot lava 800m into the sky yesterday.

Hundreds of tremors have been recorded every day since Sunday in large areas around the volcano.

Taal, which offers a picturesque view popular with travellers and tourists, roared back to life on Sunday when it ejected massive columns of steam, ash and rocks that blanketed Manila, 65km away, shutting down the capital.

Government geologists said the lava outflow seemed to have weakened.

But this did not suggest the threat was easing.

"This brief silence shouldn't be considered as a sign Taal volcano is calming down," Phivolcs science research specialist Jerome de Lima told radio station DZMM.

Phivolcs director Renato Solidum said the volcano could still belch superheated debris that could travel at great speed, skid across water and threaten a vast area around it.

"We advise (people) not to go into the 14km danger zone because of the possible pyroclastic density current," he told reporters.

Taal's previous eruptions lasted months and Mr Solidum said the alert warning of a potentially catastrophic "explosive eruption" may remain in place for weeks, depending on developments.