People gather outside a shopping mall after a powerful earthquake rocked Manila on Monday. Ted Aljibe/AFP

Five people were killed when at least two buildings collapsed as a strong earthquake rocked the northern Philippines, a local official said.

Three bodies have been pulled out of a collapsed building in the town of Porac, while an old woman and her grandchild were crushed to death by another building in the town of Lubao, provincial governor Lilia Pineda told ABS-CBN television.

"The quake has caused a blackout," she said, hampering rescue efforts in the early evening as night closed in.

The US Geological Survey says the magnitude 6.3 quake struck northwest of Manila on Monday afternoon. It says the quake was centered near the town of Gutad on Luzon island.

Philippine Institute of Seismology and Volcanology chief Renato Solidum says the quake, which was caused by movement of a local fault, was not strong enough to trigger a tsunami or cause widespread damage.

However, some officials reported damage to a church in northern Pampanga province and said boulders rolled down a mountain, blocking a highway.

Thousands of residents and office workers dashed out of buildings in Manila.

Agencies