A strong earthquake shook Taiwan (search) on Friday, forcing the Taipei subway system to shut down during the lunchtime rush. No serious damage or injuries were immediately reported.

The earthquake's epicenter was in the Pacific Ocean, about 70 miles from the Taiwanese port city of Su'ao, the Central Weather Bureau (search) said. It put the magnitude at 7, while the Golden, Colo.-based U.S. Geological Survey (search) said it had a strength of 6.7.

The tremor gently rocked buildings for about one minute and was felt on Japan's southern coast. On the city's streets, the quake caused sidewalks to shake slightly.

The quake shut down Taipei's subway system for about an hour, stranding thousands of passengers during lunchtime. It also caused a brief power outage at the world's tallest skyscraper, Taipei 101, TVBS cable news reported.

The weather bureau said the tremor was the strongest to hit the island since a 7.6-magnitude earthquake devastated central Taiwan in 1999, killing 2,300 people and demolishing thousands of homes.

Earthquakes frequently hit Taiwan but usually cause little or no damage. A magnitude 7 quake is capable of widespread, heavy damage.