A series of earthquakes including a 6.2-magnitude tremor have struck near Istanbul, shaking buildings and prompting people to flee apartment blocks.
At least 151 people were injured jumping from high places, the governor of Turkey's largest city said on X. There had been no reported deaths.
The largest earthquake on Wednesday struck at 12:49 local time (09:49 GMT) at a depth of 6.92 km (4.3 miles), Turkey's emergency services said.
The epicentre of the 6.2-magnitude tremor was located along the coast of the Sea of Marmara, in the Silivri area about 80 km (50 miles) west of Istanbul. City authorities said more than 50 aftershocks had been recorded in the hours since.
Residents reported the main earthquake as one of the strongest they had felt in years.
Authorities said an abandoned building in the Fatih district on the European side of the city had collapsed.
Energy and gas supplies, drinking water and sewerage infrastructure were unaffected, it added in a post on X.
Schools are to close on Thursday and Friday, Education Minister Yusuf Tekin said. He added that school garden areas would remain open for use as safe spaces.
Selva Demiralp, an economics professor at Koç University, told the BBC she was with her family in a high-rise when the earthquake struck and it was "quite scary".
"Somehow, in the midst of the earthquake, we felt a deep sense of comfort—because the whole family was together," she said.
"We are safe, it looks there was no damage in buildings," she said. But she added that people were nervous about whether the quake "was a foreshock itself" and the "real one is on its way".
Southern Turkey was devastated by two giant earthquakes in 2023, which killed more than 55,000 people.
Istanbul is Turkey's most populous city and home to 16 million people - a fifth of the country's residents. The city lies 20km to the north of the North Anatolian Fault Line.
Additional reporting by Mallory Moench