ATHENS - A tremor with a magnitude of 5.6 shook the Dodecanese island of Karpathos in Southeastern Greece early on Sunday but causing no injuries, officials said.

"The epicentre of the earthquake, measured at 5.6, was in the sea, southwest of Karpathos island. Earthquakes of this magnitude are usual in the area," an Athens Geodynamic Institute official told Reuters.

The fire brigade said the quake was felt on Karpathos but no injuries were reported.

A series of quakes in the past months have shaken western Greece and popular tourist islands, including Zakynthos in the Ionian Sea.