An earthquake with a preliminary magnitude of 5.2 struck off the southern Greek resort island of Crete, authorities said.
There were no immediate reports of injuries or damage.
The Athens Geodynamic Institute said the undersea earthquake occurred at 7.23pm local time on Wednesday between Crete and the islet of Gavdos.
It had a depth of 11.6 kilometres (seven miles).
The Fire Service said it had received no initial reports of injuries or damage to buildings.
Greek media said the earthquake was felt across Crete – a popular summer tourist destination.
Greece is in one of the world’s most seismically active areas, and earthquakes are common, though most are not felt.
Deaths and severe damage are rare. But in 1999, a magnitude-5.9 earthquake near Athens killed 143 people.