A 6.7 magnitude earthquake rocked the Greek Island of Kos early Friday, killing at least two people and injuring scores more, officials say.
Mayor George Kyritsis told CNN Greece that at least two people -- a Swedish and a Turkish national -- have died.
The quake's epicenter was just 16.2 kilometers (10.1 miles) east-northeast of Kos, in the sea between Greece and Turkey, the US Geological Survey said.
At least five people on Kos were seriously injured after the quake hit, South Aegean region Gov. George Hadjimarkos told Greek TV channel Skai.
Hadjimarkos said that the two fatalities occurred when the roof collapsed at a bar in a 1920s building in the old part of Kos. That area of town is known for its bars and is popular with tourists.
About 200,000 tourists were on the island at the time of the quake, according to Konstantina Svinou, president of the Hoteliers Association of Kos.
Svinou told local broadcaster ERT that ferries are currently unable to dock at the port of Kos due to damage and that local authorities are working to restore services.
Over the strait in Turkey, the Kandilli Research Center at Bogazici University reported that 80 people had been injured in the country, but said there had been no fatalities.
English holidaymaker Mary Marioni, 73, had been staying on the island for the last two weeks with her husband when the quake hit.
"The hotel is still standing but we can't get to our rooms as many were badly damaged, so we are still around the pool. We slept on sunbeds from 1:45 a.m. under the stars," Marioni told CNN.
"Everyone is still very shattered. We were rocked in our beds twice, then we all went outside. We have been experiencing small tremors all the time since the two big ones but it's nothing in comparison."
The USGS estimated that approximately 200,000 people in Greece and Turkey felt strong to very strong shaking from the earthquake. Video from Kos shows rubble in the streets and shops trashed.
Photos and video from the area show that a number of the island's historic buildings have suffered extensive damage.
An eyewitness, identified only as Eva, said she saw a mosque that had been razed by the quake. She added that there were "many" people injured who were covered in blood.
"The table started to shake," at 1:31 a.m., she told CNN affiliate CNN Greece, adding that the situation was "chaos."
"Never before had I experienced something like that," she said. "I was in Athens during the 1999 earthquake but it was not like this one. The sea began to rise and everybody started to run toward higher ground."
She said people in the streets were running in panic. "What else they could do? They were falling over each other."
Seaside resort struck
The epicenter was also close to the Turkish port city of Bodrum, a seaside resort popular with tourists and Turks alike. It is also a major transit point for migrants and refugees trying to reach Europe.
A video posted to Instagram by Firuz Anlı shows people in Bodrum experiencing the tremor. The group is celebrating a birthday on a seaside patio, when the lights appear to go out and several centimeters of water spill onto deck.
CNN Senior International Correspondent Arwa Damon, who was staying in a village about half an hour away from Bodrum, said she felt the quake strike at about 1:30 a.m. (6:30 p.m. ET) and that it lasted for about ten seconds.
At least a dozen aftershocks shook the area over the three hours following the initial quake, she said.
Damon added that there were no reports of collapsed buildings, although she did see some families camped outdoors, fearful of buildings weakened by the quake and possible, subsequent aftershocks.
A hospital was reportedly evacuated, she said, as its mezzanine was damaged.
Bodrum Mayor Mehmet Kocadon, speaking to Turkey's state news agency Anadolu, said one road had collapsed and some boats were damaged as the lines holding them were snapped by strong waves.
Turkey is no stranger to earthquakes, with smaller ones taking place in the country on a regular basis. This one, however, was jarring "not only because of the intensity of it but also because the aftershocks went on for so long," Damon said.
Bodrum is about 700 kilometers (435 miles) from Istanbul and also from Ankara.
A quake with a magnitude of between 6.0 and 6.9 is classified as "strong." According to the USGS, there were at least six aftershocks of magnitude 4.0 or greater.
CNN meteorologist Karen Maginess said that the tremblor, which occurred at a relatively shallow depth of 10 km (6 miles), is considered a major earthquake.
Aftershocks will continue for weeks, maybe months, she said.