Deadly quake rattles Philippines

ZAMBOANGA CITY, Philippines (CNN) -- Four people were killed and six injured after a powerful earthquake rocked the southern Philippines.

The quake, which struck the island of Mindanao at dawn on Wednesday, had a magnitude of 6.8, according to the Philippine Institute of Volcanology and Seismology.

Thousands of people have been evacuated from their homes in the worst hit province of Sarangani as a precautionary measure.

The victims were killed and injured as a result of falling debris, according to the National Disaster Coordinating Council.

The earthquake toppled two churches and a health center in the region of South Cotabato and destroyed a public market in the southwest province of Sultan Kudarat.

The tremors also brought down several walls in General Santos City and spurred a landslide.

The quake's epicenter, located undersea, is estimated to be 81 kilometers (50 miles) southwest of Sultan Kudarat.

The Philippine lies in the Pacific "ring of fire" where volcanic activities and earthquakes are common.

Wednesday's tremor was the strongest to hit the Philippines since a 7.7 magnitude tremor killed more than 1,600 people on the main island of Luzon in 1990.

The Philippines registers around 1,700 earthquakes a year, but only around 16 strong enough to be felt.