An magnitude-6.4 earthquake struck off the eastern coast of China's Taiwan region at 5:46 p.m. on Monday at a depth of 15 kilometers, the China Earthquake Networks Center (CENC) said.

The quake was initially measured at a magnitude of 6.0.

There are no immediate reports of damage or casualties. 

The tremor was felt across the island, local media reported, and also in some mainland cities across the Taiwan Straits, such as Fuzhou and Xiamen in Fujian Province.