A powerful earthquake hit the southern Philippine island of Mindanao on Sunday, killing a child, injuring dozens and damaging buildings in an area still recovering from a string of deadly quakes in October. Police said a rescue operation had been launched at a heavily damaged market building in Padada near the 6.8 magnitude quake's epicentre, which is about 90 kilometres (55 miles) south of the major city of Davao. Patients were evacuated from hospitals as a precaution and nervous crowds massed outside shopping malls after the jolt and dozens of smaller, but strong aftershocks. "We can no longer use our office because the walls cracked and the stairs collapsed," local police spokeswoman Lea Orbuda told AFP. "The power is off and the water taps are dry." A provincial police commander said the number of injured across the hardest hit areas had reached 62, with one confirmed fatality after a child was crushed under a collapsed structure. The commander, Alberto Lupaz, said there appeared to be some people trapped under the damaged market building but rescue efforts had been delayed. "They (rescuers) were attempting to check the rubble... the aftershocks were too strong," Lupaz said. President Rodrigo Duterte, who is from Davao, was caught up in the earthquake but was unharmed, officials said. "The First Lady... said the car she was riding (in) was swaying," spokesman Salvador Panelo said. "They are unhurt." There was no threat of a tsunami, said the US Geological Survey, which initially reported the magnitude at 6.9. The Philippines is situated on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches from Japan through Southeast Asia and across the Pacific basin. Three quakes above 6.0 magnitude hit roughly the same area of Mindanao in a matter of weeks in October, killing some two dozen people and heavily damaging office buildings, schools and apartments. Tens of thousands of people were forced into shelters by the string of tremors, the government said, either because their homes were damaged or they were too afraid to return. Most of the deaths in October were due to collapsing walls and falling debris, including a teenage boy who was crushed by a falling wall as he tried to escape his school. Other fatalities were attributed to rock and landslides unleashed by the violent shaking that injured at least 400 people. The Philippines has been hit by several very powerful earthquakes in recent decades, including one of magnitude 7.8 that struck the northern resort town of Baguio in 1990. That tremor toppled multi-story buildings and hotels, killing some 1,200 people. A house pancaked by the earthquake in Padada on the southern Philippine island of Mindanao Map locating a 6.8 magnitude earthquake which hit the southern Philippines on Sunday.