The earthquake hit both Greece and Turkey in popular summer resort locations killing two tourists in Greece and injuring hundreds.
At least two people were killed and about 460 injured early on Friday when a magnitude 6.7 earthquake shook the popular summer resort holiday destinations of the Dodecanese Islands in Greece and the Aegean coast of Turkey.
Two tourists, a Turkish national and a Swedish national were killed on the Greek island of Kos, Greek authorities said. More than 100 people were also injured. The quake caused injury and damage, the ANA news agency cited the island's mayor as saying.
Across a narrow Aegean Sea waterway in Turkey's Bodrum, nearly 360 people were admitted to hospital, with injuries suffered in their attempts to flee the overnight tremor, which struck at 1:31 am local time (2230 GMT).
TRT World's Oliver Whitfield-Miocic reports.
It was the second quake of a magnitude exceeding 6.0 in the broader region this year, a level that can cause considerable damage.
The epicentre of the quake was approximately 10.3 kilometres (6.4 miles) south of the major Turkish resort of Bodrum, a magnet for holiday makers in the summer, and 16.2 (10 miles) kilometres east of the island of Kos in Greece, the US Geological Survey said.
It had a depth of 10 kilometres (6.2), USGS said.
The European quake agency EMSC said a small tsunami could be caused by the quake, but Turkish broadcasters cited officials saying large waves were more likely.
Turkey evacuates citizens from Kos
The Turkish foreign ministry said its consulate on the Greek island of Rhodes had confirmed the death of the Turkish citizen and was trying to contact the family.
The consulate added that one other Turkish citizen has been seriously injured and taken to Athens.
A ferry has also been sent to evacuate 200 Turkish nationals from Kos back to Bodrum.
CNN Turk broadcaster and other local media said the evacuations had begun.
In the Turkish resort of Bodrum, television pictures showed throngs of worried residents and holidaymakers in the streets.
"The biggest problem at the moment are electricity cuts in certain areas [of the city]," Bodrum mayor Mehmet Kocadon told NTV television.
"There is light damage and no reports that anyone has been killed" in the area.
The governor of the southern Mugla province — where Bodrum is located — said some people had been slightly injured after falling out of windows in panic.
The quake was also felt on the Datca peninsula — also a major resort area — as well as Turkey's third city of Izmir on the Aegean to the north.
An AFP correspondent holidaying in Bodrum said the major earthquake had been followed by several aftershocks.
"The bed shook a lot. Some bottles fell and broke in the kitchen and the patio," said Turkish pensioner Dilber Arikan who has a summer house in the area.
"I screamed; I was very scared because I was alone."
The quake was also felt by holidaymakers on the Greek island of Rhodes.
"We were very surprised. We were scared and we immediately went outside," Teddy Dijoux, who was holidaying with his family at a Rhodes resort, said.
"That lasted a long time. I quickly gathered up my children to leave the hotel," said holidaymaker Sylvie Jannot.
Ali Pinar, manager of the Regional Earthquake-Tsunami Monitoring Center at Bogazici University explains how the earthquake happened.
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 significant earthquakes, which brought back memories of past deadly earthquakes.
In June, a 6.3-magnitude earthquake gutted a village on the Greek island of Lesbos, killing a woman and leaving more than 15 injured. The quake also caused panic on Turkey's Aegean coast.
On August 17, 1999, a huge earthquake measuring more than 7.0 magnitude near the city of Izmit devastated vast areas in the country's densely populated northwestern zone, notably around Istanbul, killing over 17,000 people.