MANILA -- An earthquake with a magnitude of 6.1 hit the southwest Philippines early Sunday, according to the US Geological Survey (USGS).
The epicenter of the quake was located 113 miles (182km) northwest of Manila at a depth of 22 miles (35km) when it struck at 6:18am local time, the USGS said.
There were no reports of casualties and no tsunami alert was issued.
The Philippine Institute of Volcanology and Seismology measured the quake at 6.0 magnitude, AFP reported.
The quake was felt in some areas, including Manila, but there were no immediate reports of damage or injuries, said civil defense chief Benito Ramos.
The Philippines sits on the Pacific Ring of Fire -- a belt around the Pacific Ocean dotted by active volcanoes and unstable ocean trenches.
One fault line runs directly under Manila, a metropolis of more than 12 million people, and government seismologists have warned the city is unprepared for a major quake.
In February, a 6.7-magnitude earthquake in the central Philippines triggered landslides that left more than 100 people dead or missing.