A strong earthquake shook the northern Philippines on Wednesday, causing some damage and prompting people to flee buildings in the capital. Officials said no casualties were immediately reported.

The 7.3 magnitude quake was centered around Abra province in a mountainous area and several aftershocks have followed, the Philippine Institute of Volcanology and Seismology said.

The quake was set off by movement in a local fault at a depth of 25 kilometers (15 miles), the institute said, adding it expected damage and more aftershocks.

Officials said the strong shaking caused cracks in buildings and houses.

The U.S. Geological Survey measured the quake's strength at 7.0 and depth at 10 kilometers (6 miles). Shallower quakes tend to cause more damage.

The Philippines lies along the Pacific "Ring of Fire," an arc of faults around the Pacific Ocean where most of the world's earthquakes occur. It is also lashed by about 20 typhoons and tropical storms each year, making it one of the world's most disaster-prone countries.

A magnitude 7.7 quake killed nearly 2,000 people in the northern Philippines in 1990.