A magnitude 6.3 earthquake struck the central Philippines on Monday, the US Geological Survey (USGS) said, and a Reuters witness said office buildings swayed in the main business district of the capital, Manila.
The quake struck 60 km northwest of Manila at a depth of 40 km. The USGS initially said the magnitude was 6.4 but later downgraded it slightly.
There were no immediate reports of casualties or damage. Some people evacuated their offices 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.