The biggest of the tremors to hit Istanbul was felt some 275 miles away (440km) in the capital, Ankara, according to Mayor Mansur Yavas. It's a measure of how powerful the 6.2-magnitude quake was. Officials from the Istanbul Governorship say they haven't received any reports of earthquake damage yet.

A strong, 6.2-magnitude earthquake struck in the Sea of Marmara on Wednesday, according to the United States Geological Survey. The temblor happened at 12:49 p.m. Eastern European time about 25 miles southwest of Istanbul, data from the agency shows.

A strong earthquake rattled Istanbul, Turkey, and neighboring regions, sending panicked people pouring into streets but apparently causing no major damage.