TAIPEI, July 23 (Reuters) - An earthquake measuring 6.0 on the Richter scale rattled Taiwan on Monday, but there were no immediate reports of casualties or damage, officials said.

The epicentre of the quake, which struck at 9:40 p.m. (1340 GMT) was about 33 km east of Hualien on the east coast, at a depth of 30 km, the Central Weather Bureau said on its Web site.

The United States Geological Survey put the magnitude of the quake at 5.6.

There were no immediate reports of major damage or injuries, according to a spokesman from the National Fire Agency.

Earthquakes occur frequently in Taiwan, which lies on a seismically active stretch of the Pacific basin.

One of Taiwan's worst-recorded quakes occurred in September 1999. Measuring 7.6 on the Richter scale, it killed more than 2,400 people and destroyed or damaged 50,000 buildings.