An earthquake of magnitude 6.3 struck near the south coast of Japan's island of Honshu early on Sunday, the European earthquake monitoring service EMSC reported.

The estimated population of the area where the earthquake was felt is 30 million inhabitants, EMSC said.

There were no immediate reports of damage or injuries.

Apart from Japan, another quake with a preliminary magnitude of 4.2 struck not far from Athens and seismologists say it was an aftershock from a stronger quake more than a week ago.

The Athens Institute of Geodynamics said Sunday's earthquake happened at 7:09 pm and was centered 21 kilometers (13 miles) northwest of the Greek capital. It was felt throughout the Athens area but there have been no reports of damage.

Earlier on Sunday, an earthquake of magnitude measuring 3.6 on the Richter scale had hit East Garo Hills districts of Meghalaya on Sunday morning.