Heavy rains over an erupting volcano in the eastern Philippines on Saturday threatened to trigger deadly mudflows as debris and sediment deposited on its slopes are washed out, officials warned.
Mayon Volcano in Albay province, 330 kilometres south of Manila, has been belching out ash and lava since January 13, forcing nearly 67,000 people to evacuate their homes at the foot of the mountain.
The eruption has deposited millions of cubic metres of thick pyroclastic materials and ashfall on watershed areas and slopes of Mayon Volcano, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).
"These deposits can be remobilised by rainwater and generate lahars (mud flows) by themselves and or by incorporating existing erodible material on channel banks," Phivolcs warned in an advisory.

Residents using a net try to catch recyclable materials along a river near Mayon volcano in Daraga town, Albay province, south of Manila on Saturday.

The institute has already monitored "some signals" of mud flows from Mayon following heavy rains overnight, said Mariton Bornas, chief of the institute's volcano monitoring and eruption prediction division.
"We have fresh deposits on the slope and with the rain, it's really a dangerous combination for the communties," she said.
"Lahar from Mayon can carry huge boulders," she added. "It's very dangerous not only because it can bury communities, wash away people and everything in its path, but also because of impact."
Bornas noted that the last major disaster related to Mayon was in 2006, when a typhoon battered the province after the volcano erupted, triggering mudflows that killed 1,300 people. About an equal number of people were missing and presumed dead.
"It's a real threat so we are urging everyone to prepare and evacuate when told by authorities," she said.
The 2,463-metre volcano has erupted about 50 times since 1616. The last deadly eruption was in May 2013. Five hikers were killed and seven people injured in that incident.
Mayon's most violent eruption was in 1814, when more than 1,200 people were killed and a town was buried in volcanic mud. An eruption in 1993 killed 79 people.