A mild earthquake with an initial magnitude of 5.6 jolted an area south of Tokyo on Tuesday, according to the Japan Meteorological Agency.

The quake was, nonetheless, felt in Tokyo.

There were no immediate reports of damage, and no tsunami warning was issued.

The focus of the tremor, which struck at 6:24 p.m. (0924 GMT), was 20 km (12 miles) below the ocean floor off the Izu Peninsula in Shizuoka prefecture, about 80 km (50 miles) southwest of Tokyo, the agency said.

Some train services including Shinkansen bullet trains in the area were briefly halted as a precaution, NHK public broadcaster said.

Earthquakes are common in Japan, one of the world's most seismically active areas. The country accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater.

In October 2004, an earthquake with a magnitude of 6.8 struck the Niigata region in northern Japan, killing 40 people and injuring more than 3,000.

That was the deadliest quake since a magnitude 7.3 tremor hit the city of Kobe in 1995, killing more than 6,400.