Map locating the 6.6 magnitude earthquake in the southern Philippines
Map locating the 6.6 magnitude earthquake in the southern Philippines AFP / Jonathan WALTER

A 6.6-magnitude quake struck the southern Philippines Tuesday, authorities said, causing injuries and damaging buildings in a region still reeling from a previous deadly tremor.

Terrified locals fled into the streets after the shallow quake, which the US Geological Survey said hit the island of Mindanao as schools and offices opened for the day.

USGS initially reported the quake had a magnitude of 6.8, adding there was no tsunami threat.

"Our municipal hall has been destroyed," said Reuel Limbungan, mayor of Tulunan, a town near the epicentre.

"We are receiving lots of reports of injuries, but we have to confirm them," he told AFP.

The area is still suffering the effects of a 6.4-magnitude quake that hit less than two weeks ago, killing at least five and damaging dozens of buildings.

Residents evacuated homes across the Mindanao region including a mall that caught fire in the city of General Santos shortly after the quake struck on October 16.

The Philippines is part of the Pacific "Ring of Fire", an arc of intense seismic activity that stretches from Japan through Southeast Asia and across the Pacific basin.