A powerful 6.4-magnitude natural disaster south of the island of Zakynthos has been felt across western Greece.
Three people were taken to hospital, two of them slightly injured, a spokesman for Greece's civil protection agency told Reuters. Images from the harbor showed cracked and warped pavement near moored boats.
Tremors damaged a 15th-century monastery on the nearby islands of Strofades, local media in Zakynthos reported. "The lack of electricity is a problem, but technicians are trying to restore power". A couple of people were treated for minor injuries.
Mr Georgiou said a precautionary tsunami warning was issued, although none had materialised two hours after the natural disaster.
The U.S. Geological Survey said the undersea quake was magnitude 6.8 and its epicenter was 33 kilometers (20 miles) southwest of Mouzaki in the southern part of the island. It had a depth of 16 kilometres and struck at 22:55 GMT on Thursday.
The quake was centred 34km south-west of Zakynthos in the Ionian Sea. Measurements of quake strength can vary due to the equipment each institution uses and other factors. Geologists urged locals to seek refuge in safe areas in case powerful aftershocks triggered complete collapse.
Tourists on the popular vacation island were forced to evacuate their hotels in the middle of the night after the quake hit, Sky News reported.
The USGS estimates that up to 19.3 million people could have felt the natural disaster, including 54,000 people who may have experienced "strong" to "very strong" shaking.
Greece suffers from thousands of earthquakes per year, due to the area lying on one of the world's most quake prone regions.
The quake triggered a tsunami warning but the sea level increases were only a few centimetres.
The most recent natural disaster to claim lives, was in 1999 where the magnitude was recorded at 5.9 which killed 143 people on the outskirts of Athens.