Olympic city Athens was jolted by a small earthquake on Tuesday but there were no reports of any damage. The tremor was measured at 4.5 on the Richter scale.
Two brief jolts were felt at 3:38 pm (1238 GMT), with an epicentre some 70 kilometres (45 miles) north of the Greek capital.
According to the Athens Geodynamics Institute, the quake originated under the sea off Psachna, a town on the island of Evia.
The area has produced a string of similar earthquakes in the last 14 months, without causing any damage or losses.
"There is no ground for concern... this area produces no stronger earthquakes," said Yiorgos Stavrakakis, director of the Athens Geodynamics Institute to a radio station, adding that similar tremors might occur again in the immediate future.
Greece is one of the most earthquake-prone countries in the world and earthquakes happen almost daily in different parts of the country.