A 7.8-magnitude earthquake in the southern Philippines on Monday killed at least 31 people, according to provincial authorities, after toppling buildings and sparking tsunami warnings across the region.
National disaster authorities said at least a dozen people were still missing, while 134 had sustained injuries.
Philippine authorities urged people in affected coastal regions to move to higher ground after the offshore quake hit south of General Santos, a city of about 720,000, where at least nine were killed.
A series of powerful aftershocks rocked the area from about two hours after the first quake, according to the United States Geological Survey, with the largest measuring 6.5 magnitude.
In General Santos, an AFP journalist watched on Monday afternoon as rescue workers dug through the rubble of a popular grocery store chain in a desperate bid to reach the bodies of two employees buried beneath.
Rene Punzalan, disaster chief for hard-hit Sarangani province, told AFP 14 people had died in Glan municipality alone when a landslide buried their homes at the foot of a mountain.
"The landslide happened immediately after the earthquake, so many lives were lost," he said, adding that some areas had yet to report if they had sustained casualties.
"The greatest challenge is communication. The power was cut, so it's hard to get updates," Punzalan said.
"We're worried about aftershocks," he added. "We can feel the fear of the residents."
Videos posted to social media and verified by AFP showed a shopping centre with a Jollibee fast food restaurant reduced to rubble in General Santos City, while a school building that officials said was unoccupied crumpled in another.
"Lord, it has really collapsed! ... The building has really collapsed!" someone can be heard shouting as the abandoned school structure topples.
In another video verified by AFP, young schoolchildren could be seen screaming in the arms of their teachers as the quake violently swayed them back and forth on the ground.
A flimsy metal structure in the background collapsed as the video uploaded to the school's official Facebook page came to an end. An accompanying caption said no one was under the structure when it fell.
Evacuate now
Punzalan, the Sarangani disaster chief, told AFP that more than 2,000 people evacuated due to a morning tsunami warning were now awaiting a green light to return to their homes.
"(Authorities) are still assessing the situation now if it will be OK to send them home," he said.
A notice from the Pacific Tsunami Warning Center had said tsunami waves were possible along the coasts of the Philippines, Indonesia, Palau, Taiwan and Papua New Guinea.
But by mid-afternoon, the Philippines and other countries had cancelled their warnings.
Waves that did reach the Pacific coast of Japan, where authorities had issued a tsunami advisory, were reported to be no higher than 20 centimetres (about eight inches).
Philippine President Ferdinand Marcos, who suspended classes across Mindanao island on what was to have been the first day of school, had called on residents in coastal areas to evacuate immediately.
"Move to higher ground now. Do not wait," he said. "Your life is more important than anything left behind."
The airport in General Santos, meanwhile, has been closed until further notice, officials said.
A video verified by AFP showed what appeared to be chunks of ceiling that had collapsed onto the baggage claim area.
Earthquakes are a near-daily occurrence in the Philippines, which is situated on the Pacific "Ring of Fire", an arc of intense seismic activity stretching from Japan through Southeast Asia and across the Pacific basin.
Eastern Mindanao was rocked by a pair of earthquakes of 7.4 and 6.7 magnitude in October that killed at least eight people.
These followed a magnitude 6.9 quake days earlier that killed 76 people and destroyed or damaged 72,000 buildings in Cebu province in central Philippines, according to government figures.
