At least five people were killed on Thursday when yet another powerful earthquake, this time measuring magnitude-6.5, struck the country's southern provinces.

The Cotabato province was the worst affected, a region already devastated by two powerful earthquakes and hundreds of aftershocks this month.

Among those killed were a village leader, crushed to death when the village hall collapsed in Batasan, outside the town of Makilala.

Many homes have been evacuated and several cities have suspended school and office work, amid concern over further aftershocks.

Officials said they were concerned residents were returning to damaged homes quicker than they should to escape the current tropical heat and humidity.

Another man was pinned to death by a fallen tree and a woman died after being hit by heavy debris elsewhere in Makilala, government welfare officer Rosemarie Alcebar told The Associated Press. Two other villagers died due to quake-related injuries in Cotabato's Arakan town but details of their deaths were not immediately available, Alcebar said.

In Davao city, president Rodrigo Duterte's hometown, a five-story apartment block partly crashed down on its basement and rescue workers scrambled to bring out nine residents, one of whom was injured and brought to hospital, officials said. The residents of the 56-room building had been urged to evacuate after it was damaged by the earlier quake on Tuesday but some defied the warning.

Mr Duterte and his family were in his Davao city home at the time of the quake, but were unhurt. Engineers would check the stability of his house just to be sure there was no damage, said the head of the presidential security force.

The latest quake comes after at least eight people died in Tuesday's 6.6-magnitude tremor. Two more were missing, 395 were injured and more than 2,700 houses and buildings, including schools and hospitals, were damaged, according to the Office of Civil Defence.

And an earthquake on 16 October with a magnitude of 6.3 killed at least seven people, injured more than 200 and destroyed or damaged more than 7,000 buildings.

The Philippine archipelago lies on the so-called Pacific "Ring of Fire" the arc of faults around the Pacific Ocean where most of the world's earthquakes occur.