A powerful earthquake struck off Taiwan early Wednesday, rocking the entire island and collapsing buildings. Japan issued a tsunami alert for the southern Japanese island group of Okinawa.

Rescuers searched Thursday for dozens of people still missing a day after Taiwan's strongest earthquake in a quarter century damaged buildings, killed 10 people and left others stranded in remote areas.

In the eastern coastal city of Hualien near the epicenter, workers used an excavator to stabilize the base of a damaged building with construction materials as officials took samples of its exterior and chickens pecked among potted plants on its slanted roof.