The death toll has risen to four after a magnitude-6.7 earthquake struck the island of Taiwan Sunday night. 20 others have been reported injured.

The quake shook central Taiwanˇs Nantou County, damaging roads and buildings.

Rescuers worked overnight to clear three provincial highways that were severely blocked by rockfall and landslides. Taiwan authorities say about 90 schools were also damaged by the earthquake. Meanwhile, more than 18,000 tourists from the Chinese mainland were in Taiwan when the earthquake hit.

There have been no reports of injury from these tourists so far.