A deadly explosion has rocked a busy pedestrian street in Istanbul, killing at least four people and injuring many more. Officials said a blast hit Istiklal Avenue, one of the most famous roads in Turkey’s largest city, on Sunday afternoon.Istanbul’s governor said at least six people were killed and 53 injured in the explosion.’We wish God’s mercy on those who lost their lives and a speedy recovery to the injured,’ Ali Yerlikaya said. Have you been affected by this story? Contact zoe.tidman@independent.co.ukHelicopters and emergency vehicles descended on the scene near Taksim Square after the blast exploded. Streams of tourists were also seen running away from the area.One witness likened the sound to that of a building collapsing, then watched as panicked pedestrians streamed down his side street.Istiklal Street is among the city’s most celebrated attractions, a long pedestrian only throughway filled with shops, big chain stores, cultural sites and diplomatic outposts, including the French and Russia consulates.At least four have been killed in the explosion The area in the heart of Istanbul was crowded as usual with shoppers, tourists and families when the blast hit.A video posted online showed flames erupting and a loud bang, as pedestrians turned and ran away.Emergency services rushed to the scene in Istanbul ‘When I heard the explosion, I was petrified, people froze, looking at each other. Then people started running away,’ Mehmet Akus, a 45-year-old who works in a restraunt on the street, said. ‘What else can you do?”My relatives called me, they know I work on Istiklal. I reassured them,’ he added.Emergency services flooded to the scene after the explosion hit at 4.20pm local time (1.20pm GMT). It was not immediately clear what caused the blast. Prosecutors have opened an investigation, according to the state-run Anadolu news agency.The explosion took place near Taksim SquareThe Turkish Red Crescent said blood was being transferred to nearby hospitals in the wake of the attack.Turkey’s media watchdog imposed a temporary media ban on reporting of the explosion, which prevented broadcasters from showing videos of the moment of the blast or its aftermath. Additional reporting by agencies