MANILA, Aug 12 (AFP) — A 7.1-magnitude earthquake struck off the Philippines on Thursday, the United States Geological Survey reported, briefly triggering a tsunami warning.

The quake hit 63.3 kilometres (39.2 miles) east of Pondaguitan on Mindanao, the country's second largest island, around 1:45 am (1745 GMT) at a depth of 65 km, the USGS said.

A tsunami warning was issued briefly, according to the US Tsunami Warning System, which said the threat had passed around two hours after the quake. 

The archipelago is regularly rocked by quakes due to its location on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches from Japan through Southeast Asia and across the Pacific basin.