An offshore magnitude 7.8 earthquake rocked the southern Philippines early Monday, damaging buildings and a key access bridge in a large southern city and setting off a 1-metre (3-foot) tsunami that washed ashore on nearby coasts. At least four people were killed and more than 200 others injured, officials said. President Ferdinand Marcos Jr. urged people to go to higher ground in Philippine areas vulnerable to a tsunami, and Indonesian and Malaysian authorities also issued warnings to their nearby coastal areas. The Pacific Tsunami Warning Centre said the threat of a tsunami had largely passed about five hours after the 7:37 am quake. But it still urged people to stay alert and to heed warnings from local authorities as sea levels may fluctuate for a few more hours. The strongest quake to strike the Philippines this year was centred at sea about 13 kilometres southwest of General Santos, a city of more than 700,000 people that is a hub for tuna processing and other commerce in the southern Mindanao region of the archipelago nation. The Philippine leader said disaster-response agencies were on standby to respond. “The national government is moving and we will not leave Mindanao behind,” Marcos said.