(UPDATE) Magnitude 6.4 earthquake hits seas off Sultan Kudarat

MANILA, Philippines (Xinhua) - A magnitude-6.4 earthquake jolted seas off Sultan Kudarat at 1: 11 p.m. local time (0511 GMT) today, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported.

No casualties and losses have been reported so far.

The epicenter of the quake was initially determined at 6.08 degrees north latitude and 123.17 degrees east longitude, about 112 kilometers southwest of Kalamansig town in Sultan Kudarat, with a depth of 619 kilometers.

The US Geological Survey (USGS) earlier put the magnitude at 6.3.

PHIVOLCS said intensity II tremor was felt in Bislig town of Surigao del Sur province. The agency said it expects aftershocks.

According to PHIVOLCS Earthquake Intensity Scales, an intensity II tremor means the quake is felt by few individuals at rest indoors, and it causes hanging objects to swing slightly, and still water in containers to oscillate noticeably.

The Philippines sits on the Pacific "Ring of Fire" where continental plates collide, causing frequent seismic and volcanic activity.