A powerful earthquake has struck off northeastern Taiwan, but there were no immediate reports of casualties or damage.

Taiwan's Central Weather Bureau says the quake registered magnitude 6.5, while the U.S. Geological Survey puts it at 5.5.

The earthquake struck Sunday morning at sea, about 88 miles (141 kilometers) east of the Taiwanese county of Keelung. Keelung is about 17 miles (28 kilometers) east of the capital, Taipei.

Earthquakes frequently rattle Taiwan, but most are minor and cause little or no damage.

However, a magnitude-7.6 earthquake in central Taiwan in 1999 killed more than 2,300 people.