A magnitude 6.4 earthquake struck off the coast of northern class="mandelbrot_refrag">Greece on Saturday, some 77 km (48 miles) south-southwest of Alexandroupolis, the U.S. Geological Survey said.
_0">The USGS said the quake's depth was 10 km (six miles). There were no immediate reports of casualties or serious damage.
Residents in Istanbul in neighboring class="mandelbrot_refrag">Turkey felt a small tremor that lasted around 10 seconds.
No further details were immediately available.
(Reporting by Karolina Tagaris, Editing by Alison Williams/Mark Heinrich)