The broadcaster said ten people were injured in the village of Vrisa on the island of Lesbos, where a number of old homes collapsed.
"Dozens of homes have collapsed and village roads are blocked," regional fire service supervisor Marios Apostolides told ERT.
"We are trying to disengage a woman trapped in debris" in Vrisa, he said, adding that this area was hit hardest by the quake."
The US Geological Survey said the epicentre of the quake was in the Aegean sea 11 kilometres (6.8 miles) south of Plomari, a village on the southern coast of Lesbos, and there were several aftershocks.
Plomari Mayor Manolis Armenakas told ERT that "We have damage to several buildings, old and new. We are now evaluating the damage.
Reports said the quake was also strongly felt in the Karaburun district of Turkey's Izmir Province, as well as in Athens, Greece. There were no immediate reports of damage or casualties in Turkey.
AFP reporters in Izmir, Turkey's third-largest city, said the earthquake was felt in the city centre and caused alarm among residents.
Turkey and Greece sit on significant fault lines and have regularly been hit by earthquakes in recent years.
This year alone, Turkey's western Aegean coast was hit by several earthquakes of up to 5.5 magnitude, which brought back memories of past deadly earthquakes.
On August 17, 1999, a huge earthquake measuring more than 7.0 magnitude near the city of Izmit devastated vast zones in the country's densely populated northwestern zone, notably around Istanbul, killing over 17,000 people.
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