Istanbul: A strong explosion was heard Sunday in a busy area in the heart of Istanbul, Turkish media reported, saying that several people had been injured.

The explosion, the cause of which was unknown, occurred shortly after 4:00 pm (1300 GMT) in the famous Istiklal shopping street which is popular with locals and tourists.

The NTV television channel reported that there were "at least five to 10 injured" and showed emergency services and police deployed to the scene.

The area has been evacuated.

Images shared on social media at the time of the explosion indicated it could be heard from far away and that there were also flames.

A wide black crater is also visible on the images as well as several bodies on the ground nearby.

Istiklal avenue was affected during a series of attacks targeting Istanbul in 2015-2016 claimed by the Islamic State group.