MANILA: A magnitude-7.4 earthquake struck off the southern Philippines’ Mindanao region on Friday, killing at least six people and triggering tsunami alerts that were later lifted.

The US Geological Survey said the quake hit about 20km off Manay town at 9:43am. It followed just 11 days after a 6.9-magnitude quake in Cebu that killed 75 people.

Three miners died when a tunnel collapsed in Pantukan, while two fatalities were reported in Mati city — one from a wall collapse and another from a heart attack. A sixth victim was reported in Davao city.

The Pacific Tsunami Warning Center initially warned of waves up to three metres along the Philippines’ eastern seaboard but cancelled the alert around noon.

Authorities reported more than 100 aftershocks, some as strong as magnitude 5.0. In Davao Oriental, power and communications were disrupted, and schools and government offices were closed.

Witnesses described panic in cities as people fled schools, malls and government buildings. “The shaking was so strong… the longest time of my life,” said teacher Christine Sierte in Compostela.

The Philippines, lying on the Pacific “Ring of Fire,” is among the world’s most disaster-prone countries. Its deadliest quake-triggered disaster was in 1976, when an 8.0-magnitude tremor unleashed a tsunami that killed or left missing 8,000 people.