Two powerful earthquakes have struck off the southern Philippines, killing at least seven people and triggering tsunami warnings.

The biggest of Friday’s quakes, with a magnitude of 7.4, hit about 20km (12 miles) off Manay town in the Mindanao region just before 10am (01:00 GMT), according to the United States Geological Survey.

An aftershock with a 6.7 magnitude rocked the same area several hours later, one of scores that followed the morning quake.

The initial earthquake damaged a hospital and schools, knocked out power and prompted evacuations of coastal areas nearby.

Three miners tunnelling for gold were killed when a shaft collapsed in the mountains west of Manay during the larger quake, rescue official Kent Simeon of Pantukan town told AFP news agency.

One miner was pulled out alive and several others were injured in the remote hamlet of Gumayan, he said, adding: “Some tunnels collapsed, but the miners managed to get out.”

One person was killed in Mati city, the largest urban centre near the epicentre, when a wall collapsed, while another two suffered fatal heart attacks, officials said.

Another person was also crushed by falling debris in Davao City, more than 100km west of the epicentre, police said.

Evacuations under way

Philippine authorities issued tsunami warnings shortly after the morning quake, but by about noon local time, the Pacific Tsunami Warning Center said the tsunami threat had passed.

Small waves were detected on the Indonesian and Philippine coasts on Friday after the earthquake. The Philippines and some regions of Indonesia had urged coastal communities to evacuate after the quake struck offshore in the southern Philippines.

The tsunami centre in Honolulu, Hawaii, said that while the threat had passed, small sea fluctuations may continue. Damage from the earthquake was still being assessed.

President Ferdinand Marcos Jr, facing his latest natural disaster after a recent earthquake killed more than 70 people and back-to-back storms, said that the Philippine government was “assessing the situation on the ground and ensuring that everyone is safe”.

“I have directed the National Disaster Risk Reduction and Management Council, the Office of Civil Defence, the Armed Forces, the Philippine Coast Guard, and all concerned agencies to immediately carry out evacuations in coastal areas, activate emergency communication lines, and coordinate closely with local governments,” Marcos said, according to the Inquirer, a leading media organisation in the Philippines.

The Philippine Institute of Volcanology and Seismology “strongly advised” people living in coastal communities in the southern and central Philippines to evacuate to higher ground earlier on Friday.

Office of Civil Defence deputy administrator Bernardo Rafaelito Alejandro IV said several buildings sustained cracks in their walls, including an international airport in Davao City, but it remained operational without any flights being cancelled.

More than 200 patients were evacuated from the Manay district hospital, where tents were set up outside to shelter them after the building’s foundations cracked, Davao Oriental provincial governor Nelson Dayanghirang told the ABS-CBN network.

“I was driving my car when it suddenly swayed and I saw powerlines swaying wildly. People darted out of houses and buildings as the ground shook and electricity came off,” Jun Saavedra, a disaster mitigation officer of Governor Generoso town in Davao Oriental, told The Associated Press by phone.

Christine Sierte, a teacher in the town of Compostela near Manay, said the violent shaking started when she was in an online meeting.

“It was very slow at first, then it got stronger … That’s the longest time of my life. We weren’t able to walk out of the building immediately because the shaking was so strong,” she told AFP. “The ceilings of some offices fell, but luckily no one was injured.”