Officials issued tsunami warnings after a strong magnitude 7.8 earthquake struck off the southern Philippine island of Mindanao on Monday, with no immediate reports of deaths or major damage.Tsunami warnings were issued in the Philippines, neighbouring Indonesia and by the US Tsunami Warning System, with people in coastal areas warned to move to higher ground.DZBB radio, broadcasting from the Philippine city of General Santos about 15 km (9.3 miles) from the epicentre, reported instances of falling furniture, damage to televisions and other appliances as the area experienced aftershocks and people left their homes to seek safety.The General Santos disaster office said aftershocks were still being felt and authorities were assessing reports of damage and some injuries.In the Philippines’ Sarangani province near the epicentre, power and telecommunications were down and school classes were suspended, said local disaster chief Rene Punzalan, adding a damage assessment was underway with no reports yet of any collapsed buildings.Disaster response underway in PhilippinesPhilippine President Ferdinand Marcos Jr said authorities were moving fast to coordinate disaster response.”The national government is moving and we will not leave Mindanao behind,” Marcos said in a statement.The Philippines and Indonesia experience hundreds of quakes each year and sit on tectonically complex parts of the “Pacific Ring of Fire”, a seismically active belt stretching from South America to the Russian Far East.Phivolcs, the Philippine agency, warned of damage and tsunami waves above one metre (yard), which could continue for several hours. Indonesia’s geophysics agency BKMG said waves of 0.19 m (8 inches) had been detected so far.Benjie Ancheta, police chief of Alabel town in Sarangani, said the police building had some cracks after the quake, which occurred during their flag-raising ceremony, where some people fainted.”This is the strongest earthquake we’ve experienced,” Ancheta told Reuters by phone.Evacuation of coastal areas underwayThe German Research Centre for Geosciences said the 7.8 magnitude quake struck at a depth of 10 km (6.2 miles). It had earlier reported a magnitude of 8.2.The geophysics agencies of the Philippines and Indonesia reported magnitudes of 7.0 and 7.7, respectively.Witnesses in Indonesia’s northern city of Manado and residents and officials in the southern Philippines all said the quake was felt strongly.A spokesperson for Indonesia disaster mitigation agency said there were no reports of damage so far.Arlene Hollero, disaster chief of Maasim town in the Philippines’ Sarangani province, said their evacuation was underway in coastal villages and there were no reported casualties so far.Water receded shortly after the quake, but the seas were normal so far, she said, adding a bridge suffered some cracks and a shrine with a huge cross collapsed. “It’s devastating,” Hollero told Reuters by phone.