UPDATE 1-Strong earthquake strikes Philippines, no tsunami risk seen

A powerful earthquake struck near the southern Philippines city of Davao on Sunday, the U.S. Geological Survey said, but there was no threat of a tsunami.

The magnitude 6.8 quake was centred 61 km (38 miles) southwest of Davao on the southern island of Mindanao, at a depth of 28.2 km, the USGS said, revising down the magnitude from an earlier 6.9. The Pacific Tsunami Warning Center said there was no tsunami threat from the quake, based on available data.

There were no immediate reports of damage, but quakes of such magnitude can damage buildings. The Philippines sits on the geologically active Pacific "Ring of Fire" and experiences frequent tremors.