TINGNAN: Bulkang Mayon, muling nagbuga ng makapal na usok at abo, bandang alas-6 Huwebes ng umaga | Kuha ni Drew Zuniga #BantayMayon pic.twitter.com/UL0RwFrXuq

— ABS-CBN News (@ABSCBNNews) January 24, 2018

MANILA - Mount Mayon remained on the brink of a hazardous eruption, state volcanologists said Thursday, as the active volcano spewed more ash and lava for the fourth straight day.

At around 6 a.m., Mayon belched an ash column 2.5 kilometers into the sky while lava flowed 500 meters from its crater, research specialist Dr. Paul Alanis of the Philippine Institute of Volcanology and Seismology told DZMM.

There "is always a possibility" that Mayon will be placed under the highest alert level of 5, which means a hazardous eruption is ongoing, he said.

Muling nagbuga ng lava ang Bulkang Mayon, alas-6:11 ng umaga. | Ulat ni Jose Carretero, ABS-CBN News Legazpi #BantayMayon pic.twitter.com/Y1P0K92jQL

— DZMM TeleRadyo (@DZMMTeleRadyo) January 24, 2018

Mayon remains under alert level 4, which means a violent eruption "is possible within days," said Alanis.

There were 72,000 residents in temporary shelters, a substantial increase from about 40,000 on Monday, local officials said.

The number of displaced increased after the provincial government expanded the danger zone around the volcano to a radius of 9 kilometers from the Phivolcs-recommended 8-kilometer no-go zone.

Mayon's sporadic eruption, which began on Jan. 13, has affected 54 villages in Albay province.

• Farm damage due to Mayon activity hits P160M

With reports from Reuters; Jose Carretero, ABS-CBN News