The quake struck 60 km (37 miles) northwest of Manila at a depth of 40 km (25 miles). The USGS initially said the magnitude was 6.4 but later downgraded it slightly.
Philippine Institute of Seismology and Volcanology chief Renato Solidum says the quake, which was caused by movement of a local fault, was not strong enough to trigger a tsunami or cause widespread damage.
However, some officials reported damage to a church in northern Pampanga province and said boulders rolled down a mountain, blocking a highway.
Thousands of residents and office workers dashed out of swaying buildings in Manila.
The Philippines is on the seismically active Pacific "Ring of Fire," a horse-shoe shaped band of volcanoes and fault lines circling the edges of the Pacific Ocean.
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