By Anne Pollmann, Laura Almanza

Istanbul/Turkey - A strong earthquake has shaken the Turkish metropolis of Istanbul.

According to the Afad disaster service, the strongest quake so far today (Wednesday) had a magnitude of 6.2 and hit the city at around 11.13 a.m. (local time).

People in the metropolis left their houses and apartments after the quake, which was clearly felt in the center of the city.

There were initially no direct reports of damage. According to Afad, the epicenters were located at different points in the Sea of Marmara off the city.

Experts believe that a quake of around magnitude 7 is overdue in the metropolis of 16 million people.

According to Turkish Urban Planning Minister Murat Kurum, 1.5 million apartments and commercial units are considered to be at risk of earthquakes.

After the strong quake, numerous aftershocks shake the metropolis.

The Afad disaster service reported several quakes of magnitude 4 to 5 - all with epicenters in the Sea of Marmara off the city. Geologist Okan Tüysüz told NTV that the possibility of another major quake could not be ruled out.

"I extend my best wishes to our citizens," said Turkish President Recep Tayyip Erdogan on the X platform. "We are monitoring the situation closely".

First reported at 12.39 p.m., last updated at 1.17 p.m.