MANILA: Philippine volcanologists on Friday called for vigilance as an approaching tropical depression could develop into a super typhoon and dump heavy rain in areas near the erupting Mayon volcano -- the country's most active.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) warned that the tropical depression will bring heavy rainfall from Sunday, triggering floods and landslides, reports Xinhua news agency.

Due to this development, the Philippine Institute of Volcanology and Seismology "strongly recommended" on Friday that residents at the foot of the cone-shaped Mayon volcano in Albay province, approximately 500 km southeast of Manila, "be vigilant and ready".

The institute said the prolonged heavy rainfall could trigger lahar flows of ash and volcanic debris spewed by the volcano, which started erupting on June 8.

"The Mayon lahars can threaten communities along the middle and lower slopes and downstream of (river) channels with inundation, burial, and wash away," the institute warned, urging the provincial authorities "to move residents to high grounds should heavy rains occur".

Authorities have evacuated nearly 19,000 residents within the six-kilometer danger zone at the foot of the Mayon volcano, approximately 500 km southeast of Manila, since its ongoing unrest starting on June 8.

The Philippine Institute of Volcanology and Seismology has maintained the alert level around the Mayon volcano at 3 on a scale of 5.

Displaced people are temporarily housed in at least 27 government-run shelters.

Mayon volcano last erupted in 2018, resulting in the evacuation of more than 23,000 people from nine cities and municipalities.