A 6.4-magnitude earthquake jolted the sea off the east coast of Hualien, Taiwan at 9:42 a.m. Monday (Beijing Time), according to the China Earthquake Networks Center said.

The epicenter was monitored at 24.0 degrees north latitude and 122.5 degrees east longitude. The quake hit at a depth of seven kilometers, the center said in a statement.

The island's seismological agency measured the quake at 6.3-magnitude, with a depth of 17.5 km, adding that the epicenter was 76.2 km off Hualien County government.

Tremor was felt in many parts of Taiwan including Taipei, but there has been no immediate reports of casualties.

Southern parts of Japan's Okinawa island prefecture were also affected by the strong quake.

The Japan Meteorological Agency (JMA) measured the quake at 6.8 magnitude and issued tsunami warnings around Okinawa's Miyako and Ishigaki islands.

The JMA said that estimated 1-meter high tsunami would affect areas around Japan the islands at around 11:30 a.m. local time.