The Athens-based Institute of Geodynamics reports that a 5.2-magnitude earthquake has occurred near the northwestern Greek city of Ioannina, about 205 miles (330 kilometers) northwest of the capital Athens.
There were no reports of damages or casualties thus far.
The earthquake occurred at 11.15 p.m. local time with the epicenter at a depth of 10.5 miles (17 kilometers). It was followed by 4.1 and 3.5-magnitude tremors within eight minutes of the original earthquake.
The US Geological Survey gave the quake a slightly higher magnitude of 5.3.
Greece lies in a highly earthquake-prone zone and such strong earthquakes are far from rare.