Series of moderate quakes strike Philippines

A series of moderate earthquakes and aftershocks hit the Philippines early Sunday, with US geologists estimating the shallowest -- a magnitude-5.1 tremor -- at just one kilometre deep, but there were no initial reports of damage.

The first quake struck off the southern island of Mindanao at around 3:00 am local time (1900 GMT), some 30 kilometres (17 miles) east-northeast of the city of Cortes, according to the USGS.

It was followed by at least six moderate aftershocks, the strongest a magnitude-5.3 that was four kilometres deep, the USGS said.

There were no immediate reports of damage and no tsunami warning was issued.