A strong 5.1-magnitude tremor has hit just west of the Greek island of Cephalonia in the Ionian Sea.

The quake, which hit at 1:15 a.m. local time (2315 GMT), had its epicenter 5 kilometers (3.1 miles) underwater, the Athens Geodynamic Institute reports.

There have been no immediate reports of damage or injuries.

A 4.7-magnitude quake hit the island Friday.

The area often produces very strong quakes. The island was flattened in 1953 by a 7.2-magnitude tremor.