The epicenter of the quake was in the Ionian Sea near the Greek island of Zante and about 50 miles northeast of the city of Pyrgos.
The quake had a depth of about 16 kilometers.
The US Geological Survey (USGS) said losses were possible.
A witness said online: "Me and my partner stay in Zante, woke up my partner, and we had three aftershocks, much smaller, the larger earthquake has moved several objects across the room."
Another witness described the earthquakes of the European-Mediterranean Seismological Center (EMSC) as "extremely violent shaking".
He added: "Objects fell
" Loud rumblings. "
The quake reportedly lasted 1
Local media reported that a 15th-century monastery in the Strofades area Italy's news station Il Messaggero reported that the earthquake could be felt to the south Italy 1965.
According to the USGS, firefighters in the regions of Sicily, Calabria and Puglia received thousands of phone calls after the quake
According to the USGS, a local small tsunami is possible and residents were advised to move away from the shores.
A 6.8 earthquake is listed by the USGS as "very strong" with the potential for "moderate" damage.
19659002] The scientific authority claimed that 19.3 million people could have felt the earthquake, including 54,000, shook people who might be "strong" to "very strong"
The USGS said: "Overall, the population in this region lives in structures that are a mix of vulnerable and earthquake-resistant structures.
"Some damage This is possible and the impact should be relatively localized."
Greece is located in one of the world's regions most affected by earthquakes, with thousands of earthquakes registered each year.