In this photo released by China's Xinhua News Agency, rescuers search for survivors at a quake site in Tainan, Taiwan on Feb. 6, 2016. (Zhang Guojun/Xinhua via AP)
Rescue workers search a collapsed building from an early morning earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo/Wally Santana)
A child is rescued from a toppled building after a 6.4-magnitude earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo)
Rescue workers guide a man from the rubble of a toppled building after an earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo)
A man is rescued from a collapsed building after an earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo/Wally Santana)
A man breaks down after seeing the body of a relative recovered from a collapsed building following an earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo/Wally Santana)
A rescue team member searches for missing people in a collapsed building, after an early morning earthquake in Tainan, Taiwan on Feb. 6, 2016. (AP Photo/Wally Santana)
TAINAN, Taiwan -- Authorities in southern Taiwan say more than 100 people are still missing after a strong earthquake caused a high-rise residential building to collapse.