ATHENS: A strong quake of magnitude 6.8 struck off Greece early on Friday, the US Geological Survey said, but there were no initial reports of damage or casualties.
The epicentre of the quake, initially reported as a magnitude 7.0, was in the Ionian Sea, some 83 miles (133.5km) southwest of Patras in the Peloponnese.
A fire brigade official in Athens said there were no early reports of damage or casualties.
The quake was fairly shallow, only 10.3 miles (16.5km) below the seabed, which would have amplified the shaking.
It struck at 1:54am (2254 GMT Thursday) and was followed about half an hour later by a 5.2 aftershock.
Greece straddles two tectonic plates and often gets earthquakes.