The tremor struck at 7:12 pm (1112 GMT), prompting the Philippine seismology office to warn of "life-threatening wave heights" and urge coastal residents to "immediately evacuate to higher grounds or move farther inland"

The aftershock, the largest of at least 300 recorded so far, came fewer than 10 hours after the Pacific seaboard of the southern major island of Mindanao was rocked by a 7.4-magnitude temblor, killing at least six people.

In Mati city, close to the offshore epicentre of both quakes, the latest one knocked out power.

In Davao city, more than 100 kilometres (652 miles) to the west, a plane that had just landed with an AFP photographer on board shook as the crew prevented passengers from immediately deplaning.

They were later allowed to disembark, but were made to wait outside on the tarmac, instead of being taken inside the passenger terminal.

There were no immediate reports of casualties or damage from the aftershock.