At least five aftershocks of 3.8 magnitude or more shook Tainan 30 minutes after the initial 6.4 quake
At least 14 people have been killed and more than 100 are missing after a 6.4-magnitude earthquake struck Taiwan, causing a number of buildings to collapse.
Eleven of the dead - including a 10-day-old girl - were killed when a 17-storey apartment building came down in the city of Tainan.
Two others were killed by falling objects elsewhere in the city.
Firefighters said more than 240 people have been rescued from the building so far, and dozens have been taken to hospital.
Authorities say 475 people have been injured in the city, but 368 of them had been discharged from hospitals by late Saturday afternoon.
Taiwanese television showed survivors being taken away from the high-rise building, including an elderly woman in a neck brace and others wrapped in blankets.
Dozens of others were rescued or safely evacuated from damaged structures or buildings declared unsafe following the earthquake, including a market and a seven-floor building.
A bank building also shook, but no one was injured or trapped.
The government's emergency centre said buildings in nine other locations in Tainan had collapsed and five have been left tilting at alarming angles.
Reporters said they could hear cries of help from inside one destroyed building.
Tainan resident Brent Brown told Sky News: "I awoke to my girlfriend saying, 'Oh my god'.
"I could feel the sensation of being thrown about and heard things crashing in the living room and kitchen of the apartment.
"The first thought that crossed my mind was that the building was either falling or was going to fall.
"I was worried those were the last moments. I hugged my girlfriend and told her I loved her, expecting the worst."
A 71-year-old neighbour of one collapsed building, who gave his name as Chang, said: "I was watching TV and after a sudden burst of shaking, I heard a boom.
"I opened my metal door and saw the building opposite fall down."
The US Geological Survey said the quake struck at a depth of six miles (10km), about 27 miles (43km) southeast of Tainan.
Tremors were felt in the capital Taipei, on the other side of the island, but there was no obvious damage there.
The quake was initially reported as having a magnitude of 6.7, but was later downgraded to 6.4.
Taiwan President Ma Ying-jeou said authorities were not clear on the extent of the disaster.
"The disaster situation is not very clear yet," he said. "We will do our utmost to rescue and secure (survivors)."
At least five aftershocks of 3.8 magnitude or more shook Tainan 30 minutes after the initial quake.
The Pacific Tsunami Warning Center said a tsunami was not expected.
Taiwan lies between two tectonic plates in the Pacific Ring of Fire and is regularly hit by earthquakes.
In 1999, a 7.6-magnitude quake killed around 2,400 people.