TAIPEI, Taiwan (AP) _ A strong earthquake shook central Taiwan on Sunday, causing rock slides and injuring more than 20 people, officials and seismologists said. No deaths were reported.

The quake, with a preliminary magnitude of 6.7, was centered about 30 miles north of Mount Yu, Taiwan's highest mountain, about 180 miles south of the capital, Taipei, the Central Weather Bureau said. The U.S. Geological Survey in Golden, Colo., which uses a different scale than the Central Weather Bureau, measured the quake at 6.2.

Taiwan's Disaster Rescue Center said more than 20 people were injured in the early morning quake, with many hit by falling rocks on mountainous highways or falling objects at home.

State radio reported that a baby was injured when it was thrown out of his cradle by the quake.

The quake was followed by seven aftershocks with magnitudes between 4 and 5, the Central Weather Bureau said. All the quakes, including the first, were considered aftershocks of a 7.6-magnitude earthquake that devastated the region in September, killing 2,400 people and destroying thousands of homes.

Seismologists at the bureau said it is not unusual for aftershocks from a major earthquake to continue for a year or more.

Located along the earthquake-prone Pacific Rim and crisscrossed by 51 fault lines, Taiwan is hit by scores of earthquakes each year, but few cause serious damage.