ATHENS, Oct. 26 (Xinhua) -- A strong earthquake measuring 6.4 on the Richter scale hit western Greece early Friday, with no casualties reported so far, Greek seismologists said.

The tremor's epicenter was located in the sea area some 53 km southwest of Zakynthos island in the Ionian Sea at a depth of 10 km, according to preliminary estimates of the Athens Geodynamic Institute.

Although there were no casualties reported to the authorities, the island has been hit by electricity cuts, according to the Greek national news agency AMNA.

Following the quake which was recorded at 1:53 a.m. local time (2253 GMT on Thursday), a strong 5.4-magnitude aftershock was reported.