ATHENS — A powerful undersea earthquake has rattled Greece’s island of Crete and was felt in the southern mainland.

The U.S. Geological Survey gave a preliminary magnitude of 6.0 for the quake, which occurred at 9:23 a.m. on Wednesday at a depth of 71 kilometers (44 miles).

There were no initial reports of any damage or injury from the temblor, a day after a powerful quake in neighboring Albania killed at least 25 people and caused damage in the coastal city of Durres and nearby areas.

“Earthquakes at this depth are normally single events and are not followed by many aftershocks,” said seismologist Efthimis Lekkas, head of Greece’s Earthquake Planning and Protection Organization. “So there is no serious cause for concern.”

The strong earthquake measuring 6.1 on the Richter scale recorded between the islands of Kythera and Crete on Wednesday is not related to the Albanian earthquake, Professor of Seismology Akis Tselentis said to the Athens-Macedonian News Agency (ANA).

“It is an earthquake independent of the Albanian one and because of its large focal depth – about 70 kilometers – it will have no continuity. Such kind of earthquakes happen once and for all. Moreover, such earthquakes are widely felt because of their focal depth,” Tselentis said.