MANILA -- Fifteen people were reported dead and at least 134 others injured after a magnitude 7.8 earthquake struck Sarangani province in the southern Philippines Monday morning, authorities said.

Rodrigo Sosmena, local civil defence office director, said the 12 deaths include three in Sarangani province and nine in South Cotabato province, including seven in General Santos, a city with a population of some 700,000.

The Philippines' National Disaster Risk Reduction and Management Council said it is validating reports that three people also died in Davao Occidental province. The Philippine National Police said in a separate report that it tallied 134 injuries.

The Philippine Institute of Volcanology and Seismology said the tectonic earthquake occurred at 7:37 a.m. local time at a depth of 33 km, with the epicenter 32 km southwest of the coast of Maasim town in Sarangani province on Mindanao Island.