MANILA - A 5.3-magnitude earthquake rocked northern Philippines Thursday morning, the United States Geological Survey (USGS) said.

The quake, whose epicenter was 66 kilometers southwest from Manila, occurred at 10:10 am, the USGS said, adding the depth of the tremor was 137 kilometers.

There was no immediate reports of casualties from Philippine authorities.

The tremor was also felt in the capital city.

Shiela Briol, a Manila resident, said that when the tremor occurred, she was at the 19th floor of a highrise building in the city. "The whole office is swaying," she said, surprised.

The Philippines sits in the so-called Pacific Ring of Fire, an area where continental plates collide producing frequent quakes and volcanic activities.