People Were Killed And Injured In An Explosion At Istanbul's Popular Istiklal Pedestrian

People were killed and injured in an explosion at Istanbul's popular Istiklal pedestrian street on Sunday, a senior official said. 

At least four people were killed and more than 30 injured on Sunday when an explosion shook a busy pedestrian street in central Istanbul, causing people to flee the blaze, according to the local governor and released videos.

Turkish broadcaster  said 11 people were injured. Istanbul Governor Ali Yerlikaya tweeted that the blast happened around 4:20 p.m.

(TRT) and that there were dead and injured but didn't say how many. The cause of the explosion was unclear. A video posted online showed flames erupting and a loud bang as pedestrians turned and ran. 

Other images showed ambulances, fire engines and police officers at the scene. Social media users said the shops and avenue were closed.

Turkey was hit by a series of deadly attacks by the Islamic State group and illegal Kurdish groups between 2015 and 2017.