MANILA: A strong earthquake shook the Philippines on Saturday, the US Geological Survey reported, but it was deep, and local authorities said they did not expect damage.

The 6.7-magnitude quake struck off the main island of Luzon at 4:48 am (2048 GMT) at a depth of 112 kilometres (70 miles), USGS said. It was followed a few minutes later with a 5.8-magnitude quake in the same region that was also deep.

"It's very strong, we're alarmed," said police Major Ronnie Aurellano in Calatagan municipality, Batangas province.