The quake was shallow, meaning its effects would have been amplified, the US Geological Survey (USGS) said.

There have also been at least five aftershocks.

Leaning ruins

Although the damage does not appear to be widespread, a number of tall buildings have been left leaning precariously.

Television pictures showed rescue workers frantically trying to reach people trapped in collapsed buildings, using ladders to climb over piles of rubble.

More than 220 people have been rescued.

But Interior Minister Chen Wei-jen said he feared more people have been in the building than usual as families gathered to celebrate Chinese New Year.

Residents of the collapsed apartment block told how they were able to escape from their homes.

"I used a hammer to break the door of my home which was twisted and locked, and managed to climb out," one woman told local TV.

Another man tied clothes together to make a rope and lowered himself from the ninth floor to the sixth floor below, Apple Daily reports.

Irving Chu was in a hostel in central Tainan. He said he had been woken up by a tremor lasting about 40 seconds.

"It was a violent jerking motion," he told BBC World News. "The entire room was shaking. We were just holding on to things. We were shaken up."

Barry Knapp, a British man in Taiwan, said he was 240km (150 miles) north of Tainan but still felt the tremor.

"I was just in bed, about to fall asleep, and shaking started happening," he told BBC Radio 5 Live.

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"It was going on for about 20 to 30 seconds and it came in waves. It was shaking and then it eased off, but then it started shaking even harder."

There were also reports of power outages.

Saturday`s quake was felt in the capital Taipei 300 km away and there have since been several aftershocks.

A 7.6 magnitude quake in central Taiwan in 1999 killed more than 2,300 people.

Taiwan lies near the junction of two tectonic plates and often sees tremors.

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