Quake impacts

The quake initially cut power to 168,000 households in Tainan, many of whose residents lived through a massive 1999 tremor that killed about 2,400 people. Later, utility Taipower said power had been restored to all but about 900 households.

Taiwan lies in the seismically active "Pacific Ring of Fire". Television quoted Tainan residents as saying the quake felt worse than the 1999 tremor, centred in central Taiwan.

Taiwan's Formosa TV said its reporters could hear the cries of people trapped inside the collapsed apartment tower as firefighters, police and troops swarmed the area. The defence ministry said 810 soldiers had been mobilized for rescue efforts.

Firefighters hosed down part of the building to prevent a fire while others used ladders and a crane to enter upper floors. The building appeared to have collapsed onto the first story where a child's clothes fluttered on a laundry line.

Some bullet train services were suspended to the south of Taiwan as inspections were carried out on the tracks for damage, Taiwan High Speed Rail Corp said in a statement.