An earthquake of 6.4 magnitude struck off the coast of northern Greece on Saturday and was felt as far away as neighboring Turkey and Bulgaria but there were no reports of serious casualties or destruction, police and fire brigade officials said. The U.S. Geological Survey (USGS) said the quake occurred some 77 km (48 miles) south-southwest of Alexandroupolis, between the islands of Lemnos and Samothrace, at a depth of 10 km (6 miles). Greek police said the quake had caused minor damage to shops and houses on the two islands.