Ali Yerlikaya, governor of Istanbul where the earthquake was also felt, said there were no reports of damage there.

Crisscrossed by major fault lines, Turkey is among the most earthquake-prone countries in the world. More than 17,000 people were killed in August 1999 when a magnitude 7.6 earthquake struck Izmit, a city southeast of Istanbul. In 2011, an earthquake in the eastern city of Van killed more than 500.

The foreign ministers of Turkey and Greece pledged on Friday to help each other in rescue and recovery efforts. The two countries have been locked in a dispute over eastern Mediterranean energy rights.

“Greek Foreign Minister [Nikos] Dendias called our minister Mevlut Cavusoglu to wish him the best. Both ministers stressed they were ready to help each other in case of need,” the Turkish foreign ministry said.

Greece rocked

The earthquake was also felt across the eastern Greek islands and even in the Greek capital, Athens.

“We have had many earthquakes in the past, however, I have never felt one that has lasted this long,”  Anna Makris, a school counselling coordinator in Athens, told Al Jazeera.

“There is a real sense of panic and now we are worried about aftershocks,” Makris added.

Greek media said residents of Samos and other islands fled their homes, while some rockfalls were reported.

The director of the hospital in Samos said four people were treated there for light injuries. Both countries reported aftershocks.

Residents of Samos, an island with a population of about 45,000, were urged to stay away from coastal areas, Eftyhmios Lekkas, head of Greece’s organisation for anti-seismic planning, told Greece’s Skai TV.

“It was a very big earthquake, it’s difficult to have a bigger one,” said Lekkas.

Public television ERT reported the earthquake caused a mini-tsunami on Samos and a number of buildings were damaged. It caused the walls of several homes to collapse and triggered flooding in the port.