A magnitude 6.0 earthquake has struck an area of western Turkey near the town of Duzce, about 210km (130 miles) east of Turkey's largest city Istanbul.
The tremors were strong enough to be felt in Istanbul and the capital Ankara, media reports say. At least 22 people were injured.
Estimates of the quake's depth vary from 2km to 10km.
There are reports of power being disrupted in the region, as well as some residents jumping from balconies.
Another 4.7 quake was reported some 20 minutes after the first.
Turkish Interior Minister Suleyman Soylu said there had been no information about loss of life.
But Health Minister Fahrettin Koca said later there were at least 22 injured, one seriously after jumping from a height.
Security camera footage of the earthquake has been posted on social media.
Duzce was hit by a major 7.2 magnitude earthquake in 1999 which left at least 845 people dead.
It followed an even larger quake months earlier in the city of Izmit, 100km to the west, which killed more than 17,000 and left buildings in the region in a weakened state.
Some 80% of Duzce's buildings have been rebuilt since the 1999 earthquakes, the city's mayor told local media.